Complete Phase 2: Frontend implementation with React + TypeScript

Frontend Features: - React 18 + Vite + TypeScript + Tailwind CSS + Zustand - JWT authentication with automatic token refresh - Tree library with search and category filtering - Full tree navigation (decision/action/solution nodes) - Session management with notes and completion - Session history with export (Markdown/Text/HTML) - ErrorBoundary for graceful error handling Backend Fixes: - CORS: Added port 5174 to allowed origins - Sessions: Fixed JSONB datetime serialization (mode='json') Documentation: - Updated PROGRESS.md with Phase 2 completion - Updated 03-DEVELOPMENT-ROADMAP.md with checked items - Added PHASE-2.5-PERSONAL-BRANCHING.md spec Seed Data: - Added backend/scripts/seed_data.py with Password Reset tree Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
2026-01-27 22:42:22 -05:00
parent 7d96807fb1
commit cd10ecd42c
51 changed files with 9014 additions and 111 deletions
--- a/frontend/.env.example
+++ b/frontend/.env.example
@@ -0,0 +1,2 @@
+# API URL - defaults to http://localhost:8000 if not set
+VITE_API_URL=http://localhost:8000
--- a/frontend/.gitignore
+++ b/frontend/.gitignore
@@ -0,0 +1,24 @@
+# Logs
+logs
+*.log
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+pnpm-debug.log*
+lerna-debug.log*
+
+node_modules
+dist
+dist-ssr
+*.local
+
+# Editor directories and files
+.vscode/*
+!.vscode/extensions.json
+.idea
+.DS_Store
+*.suo
+*.ntvs*
+*.njsproj
+*.sln
+*.sw?
--- a/frontend/README.md
+++ b/frontend/README.md
@@ -0,0 +1,73 @@
+# React + TypeScript + Vite
+
+This template provides a minimal setup to get React working in Vite with HMR and some ESLint rules.
+
+Currently, two official plugins are available:
+
+- [@vitejs/plugin-react](https://github.com/vitejs/vite-plugin-react/blob/main/packages/plugin-react) uses [Babel](https://babeljs.io/) (or [oxc](https://oxc.rs) when used in [rolldown-vite](https://vite.dev/guide/rolldown)) for Fast Refresh
+- [@vitejs/plugin-react-swc](https://github.com/vitejs/vite-plugin-react/blob/main/packages/plugin-react-swc) uses [SWC](https://swc.rs/) for Fast Refresh
+
+## React Compiler
+
+The React Compiler is not enabled on this template because of its impact on dev & build performances. To add it, see [this documentation](https://react.dev/learn/react-compiler/installation).
+
+## Expanding the ESLint configuration
+
+If you are developing a production application, we recommend updating the configuration to enable type-aware lint rules:
+
+```js
+export default defineConfig([
+  globalIgnores(['dist']),
+  {
+    files: ['**/*.{ts,tsx}'],
+    extends: [
+      // Other configs...
+
+      // Remove tseslint.configs.recommended and replace with this
+      tseslint.configs.recommendedTypeChecked,
+      // Alternatively, use this for stricter rules
+      tseslint.configs.strictTypeChecked,
+      // Optionally, add this for stylistic rules
+      tseslint.configs.stylisticTypeChecked,
+
+      // Other configs...
+    ],
+    languageOptions: {
+      parserOptions: {
+        project: ['./tsconfig.node.json', './tsconfig.app.json'],
+        tsconfigRootDir: import.meta.dirname,
+      },
+      // other options...
+    },
+  },
+])
+```
+
+You can also install [eslint-plugin-react-x](https://github.com/Rel1cx/eslint-react/tree/main/packages/plugins/eslint-plugin-react-x) and [eslint-plugin-react-dom](https://github.com/Rel1cx/eslint-react/tree/main/packages/plugins/eslint-plugin-react-dom) for React-specific lint rules:
+
+```js
+// eslint.config.js
+import reactX from 'eslint-plugin-react-x'
+import reactDom from 'eslint-plugin-react-dom'
+
+export default defineConfig([
+  globalIgnores(['dist']),
+  {
+    files: ['**/*.{ts,tsx}'],
+    extends: [
+      // Other configs...
+      // Enable lint rules for React
+      reactX.configs['recommended-typescript'],
+      // Enable lint rules for React DOM
+      reactDom.configs.recommended,
+    ],
+    languageOptions: {
+      parserOptions: {
+        project: ['./tsconfig.node.json', './tsconfig.app.json'],
+        tsconfigRootDir: import.meta.dirname,
+      },
+      // other options...
+    },
+  },
+])
+```
--- a/frontend/eslint.config.js
+++ b/frontend/eslint.config.js
@@ -0,0 +1,23 @@
+import js from '@eslint/js'
+import globals from 'globals'
+import reactHooks from 'eslint-plugin-react-hooks'
+import reactRefresh from 'eslint-plugin-react-refresh'
+import tseslint from 'typescript-eslint'
+import { defineConfig, globalIgnores } from 'eslint/config'
+
+export default defineConfig([
+  globalIgnores(['dist']),
+  {
+    files: ['**/*.{ts,tsx}'],
+    extends: [
+      js.configs.recommended,
+      tseslint.configs.recommended,
+      reactHooks.configs.flat.recommended,
+      reactRefresh.configs.vite,
+    ],
+    languageOptions: {
+      ecmaVersion: 2020,
+      globals: globals.browser,
+    },
+  },
+])
--- a/frontend/index.html
+++ b/frontend/index.html
@@ -0,0 +1,13 @@
+<!doctype html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8" />
+    <link rel="icon" type="image/svg+xml" href="/vite.svg" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <title>frontend</title>
+  </head>
+  <body>
+    <div id="root"></div>
+    <script type="module" src="/src/main.tsx"></script>
+  </body>
+</html>
--- a/frontend/package-lock.json
+++ b/frontend/package-lock.json
--- a/frontend/package.json
+++ b/frontend/package.json
@@ -0,0 +1,40 @@
+{
+  "name": "frontend",
+  "private": true,
+  "version": "0.0.0",
+  "type": "module",
+  "scripts": {
+    "dev": "vite",
+    "build": "tsc -b && vite build",
+    "lint": "eslint .",
+    "preview": "vite preview"
+  },
+  "dependencies": {
+    "axios": "^1.13.4",
+    "class-variance-authority": "^0.7.1",
+    "clsx": "^2.1.1",
+    "lucide-react": "^0.563.0",
+    "react": "^19.2.0",
+    "react-dom": "^19.2.0",
+    "react-router-dom": "^7.13.0",
+    "tailwind-merge": "^3.4.0",
+    "zustand": "^5.0.10"
+  },
+  "devDependencies": {
+    "@eslint/js": "^9.39.1",
+    "@types/node": "^24.10.9",
+    "@types/react": "^19.2.5",
+    "@types/react-dom": "^19.2.3",
+    "@vitejs/plugin-react": "^5.1.1",
+    "autoprefixer": "^10.4.23",
+    "eslint": "^9.39.1",
+    "eslint-plugin-react-hooks": "^7.0.1",
+    "eslint-plugin-react-refresh": "^0.4.24",
+    "globals": "^16.5.0",
+    "postcss": "^8.5.6",
+    "tailwindcss": "^3.4.19",
+    "typescript": "~5.9.3",
+    "typescript-eslint": "^8.46.4",
+    "vite": "^7.2.4"
+  }
+}
--- a/frontend/postcss.config.js
+++ b/frontend/postcss.config.js
@@ -0,0 +1,6 @@
+export default {
+  plugins: {
+    tailwindcss: {},
+    autoprefixer: {},
+  },
+}
--- a/frontend/public/vite.svg
+++ b/frontend/public/vite.svg
@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" aria-hidden="true" role="img" class="iconify iconify--logos" width="31.88" height="32" preserveAspectRatio="xMidYMid meet" viewBox="0 0 256 257"><defs><linearGradient id="IconifyId1813088fe1fbc01fb466" x1="-.828%" x2="57.636%" y1="7.652%" y2="78.411%"><stop offset="0%" stop-color="#41D1FF"></stop><stop offset="100%" stop-color="#BD34FE"></stop></linearGradient><linearGradient id="IconifyId1813088fe1fbc01fb467" x1="43.376%" x2="50.316%" y1="2.242%" y2="89.03%"><stop offset="0%" stop-color="#FFEA83"></stop><stop offset="8.333%" stop-color="#FFDD35"></stop><stop offset="100%" stop-color="#FFA800"></stop></linearGradient></defs><path fill="url(#IconifyId1813088fe1fbc01fb466)" d="M255.153 37.938L134.897 252.976c-2.483 4.44-8.862 4.466-11.382.048L.875 37.958c-2.746-4.814 1.371-10.646 6.827-9.67l120.385 21.517a6.537 6.537 0 0 0 2.322-.004l117.867-21.483c5.438-.991 9.574 4.796 6.877 9.62Z"></path><path fill="url(#IconifyId1813088fe1fbc01fb467)" d="M185.432.063L96.44 17.501a3.268 3.268 0 0 0-2.634 3.014l-5.474 92.456a3.268 3.268 0 0 0 3.997 3.378l24.777-5.718c2.318-.535 4.413 1.507 3.936 3.838l-7.361 36.047c-.495 2.426 1.782 4.5 4.151 3.78l15.304-4.649c2.372-.72 4.652 1.36 4.15 3.788l-11.698 56.621c-.732 3.542 3.979 5.473 5.943 2.437l1.313-2.028l72.516-144.72c1.215-2.423-.88-5.186-3.54-4.672l-25.505 4.922c-2.396.462-4.435-1.77-3.759-4.114l16.646-57.705c.677-2.35-1.37-4.583-3.769-4.113Z"></path></svg>
--- a/frontend/src/App.tsx
+++ b/frontend/src/App.tsx
@@ -0,0 +1,24 @@
+import { useEffect } from 'react'
+import { RouterProvider } from 'react-router-dom'
+import { router } from '@/router'
+import { useAuthStore } from '@/store/authStore'
+
+function App() {
+  const { isAuthenticated, fetchUser, setLoading } = useAuthStore()
+
+  useEffect(() => {
+    // On app load, check if we have a token and fetch user data
+    const token = localStorage.getItem('access_token')
+    if (token && isAuthenticated) {
+      fetchUser().catch(() => {
+        // Token is invalid, will be handled by interceptor
+      })
+    } else {
+      setLoading(false)
+    }
+  }, [])
+
+  return <RouterProvider router={router} />
+}
+
+export default App
--- a/frontend/src/api/auth.ts
+++ b/frontend/src/api/auth.ts
@@ -0,0 +1,35 @@
+import apiClient from './client'
+import type { Token, User, UserCreate, UserLogin } from '@/types'
+
+export const authApi = {
+  async register(data: UserCreate): Promise<User> {
+    const response = await apiClient.post<User>('/auth/register', data)
+    return response.data
+  },
+
+  async login(data: UserLogin): Promise<Token> {
+    const response = await apiClient.post<Token>('/auth/login/json', data)
+    return response.data
+  },
+
+  async refresh(): Promise<Token> {
+    const refreshToken = localStorage.getItem('refresh_token')
+    const response = await apiClient.post<Token>('/auth/refresh', null, {
+      headers: {
+        Authorization: `Bearer ${refreshToken}`,
+      },
+    })
+    return response.data
+  },
+
+  async me(): Promise<User> {
+    const response = await apiClient.get<User>('/auth/me')
+    return response.data
+  },
+
+  async logout(): Promise<void> {
+    await apiClient.post('/auth/logout')
+  },
+}
+
+export default authApi
--- a/frontend/src/api/client.ts
+++ b/frontend/src/api/client.ts
@@ -0,0 +1,66 @@
+import axios, { type AxiosError, type InternalAxiosRequestConfig } from 'axios'
+
+const API_BASE_URL = import.meta.env.VITE_API_URL || 'http://localhost:8000'
+
+export const apiClient = axios.create({
+  baseURL: `${API_BASE_URL}/api/v1`,
+  headers: {
+    'Content-Type': 'application/json',
+  },
+})
+
+// Request interceptor - add auth token
+apiClient.interceptors.request.use(
+  (config: InternalAxiosRequestConfig) => {
+    const token = localStorage.getItem('access_token')
+    if (token && config.headers) {
+      config.headers.Authorization = `Bearer ${token}`
+    }
+    return config
+  },
+  (error) => Promise.reject(error)
+)
+
+// Response interceptor - handle token refresh
+apiClient.interceptors.response.use(
+  (response) => response,
+  async (error: AxiosError) => {
+    const originalRequest = error.config as InternalAxiosRequestConfig & { _retry?: boolean }
+
+    // If 401 and not already retrying, attempt token refresh
+    if (error.response?.status === 401 && !originalRequest._retry) {
+      originalRequest._retry = true
+
+      const refreshToken = localStorage.getItem('refresh_token')
+      if (refreshToken) {
+        try {
+          const response = await axios.post(`${API_BASE_URL}/api/v1/auth/refresh`, null, {
+            headers: {
+              Authorization: `Bearer ${refreshToken}`,
+            },
+          })
+
+          const { access_token, refresh_token } = response.data
+          localStorage.setItem('access_token', access_token)
+          localStorage.setItem('refresh_token', refresh_token)
+
+          // Retry original request with new token
+          if (originalRequest.headers) {
+            originalRequest.headers.Authorization = `Bearer ${access_token}`
+          }
+          return apiClient(originalRequest)
+        } catch (refreshError) {
+          // Refresh failed - clear tokens and redirect to login
+          localStorage.removeItem('access_token')
+          localStorage.removeItem('refresh_token')
+          window.location.href = '/login'
+          return Promise.reject(refreshError)
+        }
+      }
+    }
+
+    return Promise.reject(error)
+  }
+)
+
+export default apiClient
--- a/frontend/src/api/index.ts
+++ b/frontend/src/api/index.ts
@@ -0,0 +1,4 @@
+export { default as apiClient } from './client'
+export { default as authApi } from './auth'
+export { default as treesApi } from './trees'
+export { default as sessionsApi } from './sessions'
--- a/frontend/src/api/sessions.ts
+++ b/frontend/src/api/sessions.ts
@@ -0,0 +1,51 @@
+import apiClient from './client'
+import type { Session, SessionCreate, SessionUpdate, SessionExport } from '@/types'
+
+export interface SessionListParams {
+  page?: number
+  size?: number
+  tree_id?: string
+  completed?: boolean
+}
+
+export interface SessionListResponse {
+  items: Session[]
+  total: number
+  page: number
+  size: number
+  pages: number
+}
+
+export const sessionsApi = {
+  async list(params?: SessionListParams): Promise<Session[]> {
+    const response = await apiClient.get<Session[]>('/sessions', { params })
+    return response.data
+  },
+
+  async get(id: string): Promise<Session> {
+    const response = await apiClient.get<Session>(`/sessions/${id}`)
+    return response.data
+  },
+
+  async create(data: SessionCreate): Promise<Session> {
+    const response = await apiClient.post<Session>('/sessions', data)
+    return response.data
+  },
+
+  async update(id: string, data: SessionUpdate): Promise<Session> {
+    const response = await apiClient.put<Session>(`/sessions/${id}`, data)
+    return response.data
+  },
+
+  async complete(id: string): Promise<Session> {
+    const response = await apiClient.post<Session>(`/sessions/${id}/complete`)
+    return response.data
+  },
+
+  async export(id: string, options: SessionExport): Promise<string> {
+    const response = await apiClient.post<string>(`/sessions/${id}/export`, options)
+    return response.data
+  },
+}
+
+export default sessionsApi
--- a/frontend/src/api/trees.ts
+++ b/frontend/src/api/trees.ts
@@ -0,0 +1,57 @@
+import apiClient from './client'
+import type { Tree, TreeListItem, TreeCreate, TreeUpdate } from '@/types'
+
+export interface TreeListParams {
+  page?: number
+  size?: number
+  category?: string
+  include_inactive?: boolean
+}
+
+export interface TreeListResponse {
+  items: TreeListItem[]
+  total: number
+  page: number
+  size: number
+  pages: number
+}
+
+export const treesApi = {
+  async list(params?: TreeListParams): Promise<TreeListItem[]> {
+    const response = await apiClient.get<TreeListItem[]>('/trees', { params })
+    return response.data
+  },
+
+  async get(id: string): Promise<Tree> {
+    const response = await apiClient.get<Tree>(`/trees/${id}`)
+    return response.data
+  },
+
+  async create(data: TreeCreate): Promise<Tree> {
+    const response = await apiClient.post<Tree>('/trees', data)
+    return response.data
+  },
+
+  async update(id: string, data: TreeUpdate): Promise<Tree> {
+    const response = await apiClient.put<Tree>(`/trees/${id}`, data)
+    return response.data
+  },
+
+  async delete(id: string): Promise<void> {
+    await apiClient.delete(`/trees/${id}`)
+  },
+
+  async categories(): Promise<string[]> {
+    const response = await apiClient.get<string[]>('/trees/categories')
+    return response.data
+  },
+
+  async search(query: string, category?: string): Promise<TreeListItem[]> {
+    const response = await apiClient.get<TreeListItem[]>('/trees/search', {
+      params: { q: query, category },
+    })
+    return response.data
+  },
+}
+
+export default treesApi
--- a/frontend/src/assets/react.svg
+++ b/frontend/src/assets/react.svg
@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" aria-hidden="true" role="img" class="iconify iconify--logos" width="35.93" height="32" preserveAspectRatio="xMidYMid meet" viewBox="0 0 256 228"><path fill="#00D8FF" d="M210.483 73.824a171.49 171.49 0 0 0-8.24-2.597c.465-1.9.893-3.777 1.273-5.621c6.238-30.281 2.16-54.676-11.769-62.708c-13.355-7.7-35.196.329-57.254 19.526a171.23 171.23 0 0 0-6.375 5.848a155.866 155.866 0 0 0-4.241-3.917C100.759 3.829 77.587-4.822 63.673 3.233C50.33 10.957 46.379 33.89 51.995 62.588a170.974 170.974 0 0 0 1.892 8.48c-3.28.932-6.445 1.924-9.474 2.98C17.309 83.498 0 98.307 0 113.668c0 15.865 18.582 31.778 46.812 41.427a145.52 145.52 0 0 0 6.921 2.165a167.467 167.467 0 0 0-2.01 9.138c-5.354 28.2-1.173 50.591 12.134 58.266c13.744 7.926 36.812-.22 59.273-19.855a145.567 145.567 0 0 0 5.342-4.923a168.064 168.064 0 0 0 6.92 6.314c21.758 18.722 43.246 26.282 56.54 18.586c13.731-7.949 18.194-32.003 12.4-61.268a145.016 145.016 0 0 0-1.535-6.842c1.62-.48 3.21-.974 4.76-1.488c29.348-9.723 48.443-25.443 48.443-41.52c0-15.417-17.868-30.326-45.517-39.844Zm-6.365 70.984c-1.4.463-2.836.91-4.3 1.345c-3.24-10.257-7.612-21.163-12.963-32.432c5.106-11 9.31-21.767 12.459-31.957c2.619.758 5.16 1.557 7.61 2.4c23.69 8.156 38.14 20.213 38.14 29.504c0 9.896-15.606 22.743-40.946 31.14Zm-10.514 20.834c2.562 12.94 2.927 24.64 1.23 33.787c-1.524 8.219-4.59 13.698-8.382 15.893c-8.067 4.67-25.32-1.4-43.927-17.412a156.726 156.726 0 0 1-6.437-5.87c7.214-7.889 14.423-17.06 21.459-27.246c12.376-1.098 24.068-2.894 34.671-5.345a134.17 134.17 0 0 1 1.386 6.193ZM87.276 214.515c-7.882 2.783-14.16 2.863-17.955.675c-8.075-4.657-11.432-22.636-6.853-46.752a156.923 156.923 0 0 1 1.869-8.499c10.486 2.32 22.093 3.988 34.498 4.994c7.084 9.967 14.501 19.128 21.976 27.15a134.668 134.668 0 0 1-4.877 4.492c-9.933 8.682-19.886 14.842-28.658 17.94ZM50.35 144.747c-12.483-4.267-22.792-9.812-29.858-15.863c-6.35-5.437-9.555-10.836-9.555-15.216c0-9.322 13.897-21.212 37.076-29.293c2.813-.98 5.757-1.905 8.812-2.773c3.204 10.42 7.406 21.315 12.477 32.332c-5.137 11.18-9.399 22.249-12.634 32.792a134.718 134.718 0 0 1-6.318-1.979Zm12.378-84.26c-4.811-24.587-1.616-43.134 6.425-47.789c8.564-4.958 27.502 2.111 47.463 19.835a144.318 144.318 0 0 1 3.841 3.545c-7.438 7.987-14.787 17.08-21.808 26.988c-12.04 1.116-23.565 2.908-34.161 5.309a160.342 160.342 0 0 1-1.76-7.887Zm110.427 27.268a347.8 347.8 0 0 0-7.785-12.803c8.168 1.033 15.994 2.404 23.343 4.08c-2.206 7.072-4.956 14.465-8.193 22.045a381.151 381.151 0 0 0-7.365-13.322Zm-45.032-43.861c5.044 5.465 10.096 11.566 15.065 18.186a322.04 322.04 0 0 0-30.257-.006c4.974-6.559 10.069-12.652 15.192-18.18ZM82.802 87.83a323.167 323.167 0 0 0-7.227 13.238c-3.184-7.553-5.909-14.98-8.134-22.152c7.304-1.634 15.093-2.97 23.209-3.984a321.524 321.524 0 0 0-7.848 12.897Zm8.081 65.352c-8.385-.936-16.291-2.203-23.593-3.793c2.26-7.3 5.045-14.885 8.298-22.6a321.187 321.187 0 0 0 7.257 13.246c2.594 4.48 5.28 8.868 8.038 13.147Zm37.542 31.03c-5.184-5.592-10.354-11.779-15.403-18.433c4.902.192 9.899.29 14.978.29c5.218 0 10.376-.117 15.453-.343c-4.985 6.774-10.018 12.97-15.028 18.486Zm52.198-57.817c3.422 7.8 6.306 15.345 8.596 22.52c-7.422 1.694-15.436 3.058-23.88 4.071a382.417 382.417 0 0 0 7.859-13.026a347.403 347.403 0 0 0 7.425-13.565Zm-16.898 8.101a358.557 358.557 0 0 1-12.281 19.815a329.4 329.4 0 0 1-23.444.823c-7.967 0-15.716-.248-23.178-.732a310.202 310.202 0 0 1-12.513-19.846h.001a307.41 307.41 0 0 1-10.923-20.627a310.278 310.278 0 0 1 10.89-20.637l-.001.001a307.318 307.318 0 0 1 12.413-19.761c7.613-.576 15.42-.876 23.31-.876H128c7.926 0 15.743.303 23.354.883a329.357 329.357 0 0 1 12.335 19.695a358.489 358.489 0 0 1 11.036 20.54a329.472 329.472 0 0 1-11 20.722Zm22.56-122.124c8.572 4.944 11.906 24.881 6.52 51.026c-.344 1.668-.73 3.367-1.15 5.09c-10.622-2.452-22.155-4.275-34.23-5.408c-7.034-10.017-14.323-19.124-21.64-27.008a160.789 160.789 0 0 1 5.888-5.4c18.9-16.447 36.564-22.941 44.612-18.3ZM128 90.808c12.625 0 22.86 10.235 22.86 22.86s-10.235 22.86-22.86 22.86s-22.86-10.235-22.86-22.86s10.235-22.86 22.86-22.86Z"></path></svg>
--- a/frontend/src/components/common/ErrorBoundary.tsx
+++ b/frontend/src/components/common/ErrorBoundary.tsx
@@ -0,0 +1,66 @@
+import { Component, type ReactNode } from 'react'
+import { cn } from '@/lib/utils'
+
+interface Props {
+  children: ReactNode
+  fallback?: ReactNode
+}
+
+interface State {
+  hasError: boolean
+  error: Error | null
+}
+
+export class ErrorBoundary extends Component<Props, State> {
+  constructor(props: Props) {
+    super(props)
+    this.state = { hasError: false, error: null }
+  }
+
+  static getDerivedStateFromError(error: Error): State {
+    return { hasError: true, error }
+  }
+
+  componentDidCatch(error: Error, errorInfo: React.ErrorInfo) {
+    console.error('ErrorBoundary caught an error:', error, errorInfo)
+  }
+
+  render() {
+    if (this.state.hasError) {
+      if (this.props.fallback) {
+        return this.props.fallback
+      }
+
+      return (
+        <div className="flex min-h-[400px] flex-col items-center justify-center p-8">
+          <div className="max-w-md text-center">
+            <h2 className="mb-2 text-xl font-semibold text-foreground">
+              Something went wrong
+            </h2>
+            <p className="mb-4 text-muted-foreground">
+              An unexpected error occurred. Please try refreshing the page.
+            </p>
+            {this.state.error && (
+              <pre className="mb-4 overflow-auto rounded bg-muted p-3 text-left text-xs text-muted-foreground">
+                {this.state.error.message}
+              </pre>
+            )}
+            <button
+              onClick={() => window.location.reload()}
+              className={cn(
+                'rounded-md bg-primary px-4 py-2 text-sm font-medium text-primary-foreground',
+                'hover:bg-primary/90'
+              )}
+            >
+              Refresh Page
+            </button>
+          </div>
+        </div>
+      )
+    }
+
+    return this.props.children
+  }
+}
+
+export default ErrorBoundary
--- a/frontend/src/components/common/RouteError.tsx
+++ b/frontend/src/components/common/RouteError.tsx
@@ -0,0 +1,52 @@
+import { useRouteError, isRouteErrorResponse, useNavigate } from 'react-router-dom'
+import { cn } from '@/lib/utils'
+
+export function RouteError() {
+  const error = useRouteError()
+  const navigate = useNavigate()
+
+  let errorMessage = 'An unexpected error occurred'
+  let errorDetails = ''
+
+  if (isRouteErrorResponse(error)) {
+    errorMessage = error.status === 404 ? 'Page not found' : `Error ${error.status}`
+    errorDetails = error.statusText || ''
+  } else if (error instanceof Error) {
+    errorMessage = 'Something went wrong'
+    errorDetails = error.message
+  }
+
+  return (
+    <div className="flex min-h-screen flex-col items-center justify-center bg-background p-8">
+      <div className="max-w-md text-center">
+        <h1 className="mb-2 text-4xl font-bold text-foreground">Oops!</h1>
+        <h2 className="mb-2 text-xl font-semibold text-foreground">{errorMessage}</h2>
+        {errorDetails && (
+          <p className="mb-4 text-muted-foreground">{errorDetails}</p>
+        )}
+        <div className="flex justify-center gap-4">
+          <button
+            onClick={() => navigate(-1)}
+            className={cn(
+              'rounded-md border border-input px-4 py-2 text-sm font-medium',
+              'hover:bg-accent hover:text-accent-foreground'
+            )}
+          >
+            Go Back
+          </button>
+          <button
+            onClick={() => navigate('/trees')}
+            className={cn(
+              'rounded-md bg-primary px-4 py-2 text-sm font-medium text-primary-foreground',
+              'hover:bg-primary/90'
+            )}
+          >
+            Go Home
+          </button>
+        </div>
+      </div>
+    </div>
+  )
+}
+
+export default RouteError
--- a/frontend/src/components/layout/AppLayout.tsx
+++ b/frontend/src/components/layout/AppLayout.tsx
@@ -0,0 +1,72 @@
+import { Link, useLocation, useNavigate, Outlet } from 'react-router-dom'
+import { useAuthStore } from '@/store/authStore'
+import { cn } from '@/lib/utils'
+
+export function AppLayout() {
+  const location = useLocation()
+  const navigate = useNavigate()
+  const { user, logout } = useAuthStore()
+
+  const handleLogout = async () => {
+    await logout()
+    navigate('/login')
+  }
+
+  const navItems = [
+    { path: '/trees', label: 'Trees' },
+    { path: '/sessions', label: 'Sessions' },
+  ]
+
+  return (
+    <div className="min-h-screen bg-background">
+      {/* Header */}
+      <header className="sticky top-0 z-50 border-b border-border bg-card">
+        <div className="container mx-auto flex h-14 items-center justify-between px-4">
+          <div className="flex items-center gap-8">
+            <Link to="/trees" className="text-lg font-bold text-foreground">
+              Apoklisis
+            </Link>
+            <nav className="hidden items-center gap-1 sm:flex">
+              {navItems.map((item) => (
+                <Link
+                  key={item.path}
+                  to={item.path}
+                  className={cn(
+                    'rounded-md px-3 py-2 text-sm font-medium transition-colors',
+                    location.pathname.startsWith(item.path)
+                      ? 'bg-accent text-accent-foreground'
+                      : 'text-muted-foreground hover:bg-accent hover:text-accent-foreground'
+                  )}
+                >
+                  {item.label}
+                </Link>
+              ))}
+            </nav>
+          </div>
+
+          <div className="flex items-center gap-4">
+            <span className="hidden text-sm text-muted-foreground sm:block">
+              {user?.name || user?.email}
+            </span>
+            <button
+              onClick={handleLogout}
+              className={cn(
+                'rounded-md px-3 py-1.5 text-sm font-medium',
+                'text-muted-foreground hover:bg-accent hover:text-accent-foreground'
+              )}
+            >
+              Logout
+            </button>
+          </div>
+        </div>
+      </header>
+
+      {/* Main Content */}
+      <main>
+        <Outlet />
+      </main>
+    </div>
+  )
+}
+
+export default AppLayout
--- a/frontend/src/components/layout/ProtectedRoute.tsx
+++ b/frontend/src/components/layout/ProtectedRoute.tsx
@@ -0,0 +1,27 @@
+import { Navigate, useLocation } from 'react-router-dom'
+import { useAuthStore } from '@/store/authStore'
+
+interface ProtectedRouteProps {
+  children: React.ReactNode
+}
+
+export function ProtectedRoute({ children }: ProtectedRouteProps) {
+  const { isAuthenticated, isLoading } = useAuthStore()
+  const location = useLocation()
+
+  if (isLoading) {
+    return (
+      <div className="flex h-screen items-center justify-center">
+        <div className="h-8 w-8 animate-spin rounded-full border-4 border-primary border-t-transparent" />
+      </div>
+    )
+  }
+
+  if (!isAuthenticated) {
+    return <Navigate to="/login" state={{ from: location }} replace />
+  }
+
+  return <>{children}</>
+}
+
+export default ProtectedRoute
--- a/frontend/src/components/layout/index.ts
+++ b/frontend/src/components/layout/index.ts
@@ -0,0 +1,2 @@
+export { default as AppLayout } from './AppLayout'
+export { default as ProtectedRoute } from './ProtectedRoute'
--- a/frontend/src/index.css
+++ b/frontend/src/index.css
@@ -0,0 +1,60 @@
+@tailwind base;
+@tailwind components;
+@tailwind utilities;
+
+@layer base {
+  :root {
+    --background: 0 0% 100%;
+    --foreground: 222.2 84% 4.9%;
+    --card: 0 0% 100%;
+    --card-foreground: 222.2 84% 4.9%;
+    --popover: 0 0% 100%;
+    --popover-foreground: 222.2 84% 4.9%;
+    --primary: 222.2 47.4% 11.2%;
+    --primary-foreground: 210 40% 98%;
+    --secondary: 210 40% 96.1%;
+    --secondary-foreground: 222.2 47.4% 11.2%;
+    --muted: 210 40% 96.1%;
+    --muted-foreground: 215.4 16.3% 46.9%;
+    --accent: 210 40% 96.1%;
+    --accent-foreground: 222.2 47.4% 11.2%;
+    --destructive: 0 84.2% 60.2%;
+    --destructive-foreground: 210 40% 98%;
+    --border: 214.3 31.8% 91.4%;
+    --input: 214.3 31.8% 91.4%;
+    --ring: 222.2 84% 4.9%;
+    --radius: 0.5rem;
+  }
+
+  .dark {
+    --background: 222.2 84% 4.9%;
+    --foreground: 210 40% 98%;
+    --card: 222.2 84% 4.9%;
+    --card-foreground: 210 40% 98%;
+    --popover: 222.2 84% 4.9%;
+    --popover-foreground: 210 40% 98%;
+    --primary: 210 40% 98%;
+    --primary-foreground: 222.2 47.4% 11.2%;
+    --secondary: 217.2 32.6% 17.5%;
+    --secondary-foreground: 210 40% 98%;
+    --muted: 217.2 32.6% 17.5%;
+    --muted-foreground: 215 20.2% 65.1%;
+    --accent: 217.2 32.6% 17.5%;
+    --accent-foreground: 210 40% 98%;
+    --destructive: 0 62.8% 30.6%;
+    --destructive-foreground: 210 40% 98%;
+    --border: 217.2 32.6% 17.5%;
+    --input: 217.2 32.6% 17.5%;
+    --ring: 212.7 26.8% 83.9%;
+  }
+}
+
+@layer base {
+  * {
+    @apply border-border;
+  }
+  body {
+    @apply bg-background text-foreground;
+    font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
+  }
+}
--- a/frontend/src/main.tsx
+++ b/frontend/src/main.tsx
@@ -0,0 +1,10 @@
+import { StrictMode } from 'react'
+import { createRoot } from 'react-dom/client'
+import './index.css'
+import App from './App'
+
+createRoot(document.getElementById('root')!).render(
+  <StrictMode>
+    <App />
+  </StrictMode>,
+)
--- a/frontend/src/pages/LoginPage.tsx
+++ b/frontend/src/pages/LoginPage.tsx
@@ -0,0 +1,118 @@
+import { useState } from 'react'
+import { Link, useNavigate, useLocation } from 'react-router-dom'
+import { useAuthStore } from '@/store/authStore'
+import { cn } from '@/lib/utils'
+
+export function LoginPage() {
+  const navigate = useNavigate()
+  const location = useLocation()
+  const { login, isLoading, error, clearError } = useAuthStore()
+
+  const [email, setEmail] = useState('')
+  const [password, setPassword] = useState('')
+  const [localError, setLocalError] = useState('')
+
+  const from = (location.state as { from?: { pathname: string } })?.from?.pathname || '/trees'
+
+  const handleSubmit = async (e: React.FormEvent) => {
+    e.preventDefault()
+    setLocalError('')
+    clearError()
+
+    if (!email || !password) {
+      setLocalError('Please enter both email and password')
+      return
+    }
+
+    try {
+      await login({ email, password })
+      navigate(from, { replace: true })
+    } catch {
+      // Error is set in the store
+    }
+  }
+
+  return (
+    <div className="flex min-h-screen items-center justify-center bg-background px-4">
+      <div className="w-full max-w-md space-y-8">
+        <div className="text-center">
+          <h1 className="text-3xl font-bold tracking-tight text-foreground">Apoklisis</h1>
+          <p className="mt-2 text-muted-foreground">Sign in to your account</p>
+        </div>
+
+        <form onSubmit={handleSubmit} className="mt-8 space-y-6">
+          <div className="space-y-4 rounded-lg border border-border bg-card p-6 shadow-sm">
+            {(error || localError) && (
+              <div className="rounded-md bg-destructive/10 p-3 text-sm text-destructive">
+                {localError || error}
+              </div>
+            )}
+
+            <div>
+              <label htmlFor="email" className="block text-sm font-medium text-foreground">
+                Email address
+              </label>
+              <input
+                id="email"
+                name="email"
+                type="email"
+                autoComplete="email"
+                required
+                value={email}
+                onChange={(e) => setEmail(e.target.value)}
+                className={cn(
+                  'mt-1 block w-full rounded-md border border-input bg-background px-3 py-2',
+                  'text-foreground placeholder:text-muted-foreground',
+                  'focus:border-primary focus:outline-none focus:ring-1 focus:ring-primary'
+                )}
+                placeholder="you@example.com"
+              />
+            </div>
+
+            <div>
+              <label htmlFor="password" className="block text-sm font-medium text-foreground">
+                Password
+              </label>
+              <input
+                id="password"
+                name="password"
+                type="password"
+                autoComplete="current-password"
+                required
+                value={password}
+                onChange={(e) => setPassword(e.target.value)}
+                className={cn(
+                  'mt-1 block w-full rounded-md border border-input bg-background px-3 py-2',
+                  'text-foreground placeholder:text-muted-foreground',
+                  'focus:border-primary focus:outline-none focus:ring-1 focus:ring-primary'
+                )}
+                placeholder="••••••••••"
+              />
+            </div>
+
+            <button
+              type="submit"
+              disabled={isLoading}
+              className={cn(
+                'w-full rounded-md bg-primary px-4 py-2 text-sm font-medium text-primary-foreground',
+                'hover:bg-primary/90 focus:outline-none focus:ring-2 focus:ring-primary focus:ring-offset-2',
+                'disabled:cursor-not-allowed disabled:opacity-50'
+              )}
+            >
+              {isLoading ? 'Signing in...' : 'Sign in'}
+            </button>
+          </div>
+
+          <p className="text-center text-sm text-muted-foreground">
+            Don't have an account?{' '}
+            <Link to="/register" className="font-medium text-primary hover:text-primary/90">
+              Register
+            </Link>
+          </p>
+        </form>
+      </div>
+    </div>
+  )
+}
+
+export default LoginPage
--- a/frontend/src/pages/RegisterPage.tsx
+++ b/frontend/src/pages/RegisterPage.tsx
@@ -0,0 +1,172 @@
+import { useState } from 'react'
+import { Link, useNavigate } from 'react-router-dom'
+import { useAuthStore } from '@/store/authStore'
+import { cn } from '@/lib/utils'
+
+export function RegisterPage() {
+  const navigate = useNavigate()
+  const { register, isLoading, error, clearError } = useAuthStore()
+
+  const [name, setName] = useState('')
+  const [email, setEmail] = useState('')
+  const [password, setPassword] = useState('')
+  const [confirmPassword, setConfirmPassword] = useState('')
+  const [localError, setLocalError] = useState('')
+
+  const handleSubmit = async (e: React.FormEvent) => {
+    e.preventDefault()
+    setLocalError('')
+    clearError()
+
+    if (!name || !email || !password) {
+      setLocalError('Please fill in all fields')
+      return
+    }
+
+    if (password !== confirmPassword) {
+      setLocalError('Passwords do not match')
+      return
+    }
+
+    if (password.length < 10) {
+      setLocalError('Password must be at least 10 characters')
+      return
+    }
+
+    try {
+      await register({ email, password, name })
+      navigate('/trees', { replace: true })
+    } catch {
+      // Error is set in the store
+    }
+  }
+
+  return (
+    <div className="flex min-h-screen items-center justify-center bg-background px-4">
+      <div className="w-full max-w-md space-y-8">
+        <div className="text-center">
+          <h1 className="text-3xl font-bold tracking-tight text-foreground">Apoklisis</h1>
+          <p className="mt-2 text-muted-foreground">Create your account</p>
+        </div>
+
+        <form onSubmit={handleSubmit} className="mt-8 space-y-6">
+          <div className="space-y-4 rounded-lg border border-border bg-card p-6 shadow-sm">
+            {(error || localError) && (
+              <div className="rounded-md bg-destructive/10 p-3 text-sm text-destructive">
+                {localError || error}
+              </div>
+            )}
+
+            <div>
+              <label htmlFor="name" className="block text-sm font-medium text-foreground">
+                Full name
+              </label>
+              <input
+                id="name"
+                name="name"
+                type="text"
+                autoComplete="name"
+                required
+                value={name}
+                onChange={(e) => setName(e.target.value)}
+                className={cn(
+                  'mt-1 block w-full rounded-md border border-input bg-background px-3 py-2',
+                  'text-foreground placeholder:text-muted-foreground',
+                  'focus:border-primary focus:outline-none focus:ring-1 focus:ring-primary'
+                )}
+                placeholder="John Smith"
+              />
+            </div>
+
+            <div>
+              <label htmlFor="email" className="block text-sm font-medium text-foreground">
+                Email address
+              </label>
+              <input
+                id="email"
+                name="email"
+                type="email"
+                autoComplete="email"
+                required
+                value={email}
+                onChange={(e) => setEmail(e.target.value)}
+                className={cn(
+                  'mt-1 block w-full rounded-md border border-input bg-background px-3 py-2',
+                  'text-foreground placeholder:text-muted-foreground',
+                  'focus:border-primary focus:outline-none focus:ring-1 focus:ring-primary'
+                )}
+                placeholder="you@example.com"
+              />
+            </div>
+
+            <div>
+              <label htmlFor="password" className="block text-sm font-medium text-foreground">
+                Password
+              </label>
+              <input
+                id="password"
+                name="password"
+                type="password"
+                autoComplete="new-password"
+                required
+                value={password}
+                onChange={(e) => setPassword(e.target.value)}
+                className={cn(
+                  'mt-1 block w-full rounded-md border border-input bg-background px-3 py-2',
+                  'text-foreground placeholder:text-muted-foreground',
+                  'focus:border-primary focus:outline-none focus:ring-1 focus:ring-primary'
+                )}
+                placeholder="••••••••••"
+              />
+              <p className="mt-1 text-xs text-muted-foreground">
+                Must be at least 10 characters
+              </p>
+            </div>
+
+            <div>
+              <label htmlFor="confirmPassword" className="block text-sm font-medium text-foreground">
+                Confirm password
+              </label>
+              <input
+                id="confirmPassword"
+                name="confirmPassword"
+                type="password"
+                autoComplete="new-password"
+                required
+                value={confirmPassword}
+                onChange={(e) => setConfirmPassword(e.target.value)}
+                className={cn(
+                  'mt-1 block w-full rounded-md border border-input bg-background px-3 py-2',
+                  'text-foreground placeholder:text-muted-foreground',
+                  'focus:border-primary focus:outline-none focus:ring-1 focus:ring-primary'
+                )}
+                placeholder="••••••••••"
+              />
+            </div>
+
+            <button
+              type="submit"
+              disabled={isLoading}
+              className={cn(
+                'w-full rounded-md bg-primary px-4 py-2 text-sm font-medium text-primary-foreground',
+                'hover:bg-primary/90 focus:outline-none focus:ring-2 focus:ring-primary focus:ring-offset-2',
+                'disabled:cursor-not-allowed disabled:opacity-50'
+              )}
+            >
+              {isLoading ? 'Creating account...' : 'Create account'}
+            </button>
+          </div>
+
+          <p className="text-center text-sm text-muted-foreground">
+            Already have an account?{' '}
+            <Link to="/login" className="font-medium text-primary hover:text-primary/90">
+              Sign in
+            </Link>
+          </p>
+        </form>
+      </div>
+    </div>
+  )
+}
+
+export default RegisterPage
--- a/frontend/src/pages/SessionDetailPage.tsx
+++ b/frontend/src/pages/SessionDetailPage.tsx
@@ -0,0 +1,206 @@
+import { useEffect, useState } from 'react'
+import { useParams, useNavigate } from 'react-router-dom'
+import { sessionsApi } from '@/api'
+import type { Session, SessionExport } from '@/types'
+import { cn } from '@/lib/utils'
+
+export function SessionDetailPage() {
+  const { id } = useParams<{ id: string }>()
+  const navigate = useNavigate()
+  const [session, setSession] = useState<Session | null>(null)
+  const [isLoading, setIsLoading] = useState(true)
+  const [error, setError] = useState<string | null>(null)
+  const [isExporting, setIsExporting] = useState(false)
+  const [exportFormat, setExportFormat] = useState<'markdown' | 'text' | 'html'>('markdown')
+
+  useEffect(() => {
+    if (id) {
+      loadSession()
+    }
+  }, [id])
+
+  const loadSession = async () => {
+    setIsLoading(true)
+    setError(null)
+    try {
+      const data = await sessionsApi.get(id!)
+      setSession(data)
+    } catch (err) {
+      setError('Failed to load session')
+      console.error(err)
+    } finally {
+      setIsLoading(false)
+    }
+  }
+
+  const handleExport = async () => {
+    if (!session) return
+    setIsExporting(true)
+    try {
+      const options: SessionExport = {
+        format: exportFormat,
+        include_timestamps: true,
+        include_tree_info: true,
+      }
+      const content = await sessionsApi.export(session.id, options)
+
+      // Create download
+      const blob = new Blob([content], { type: 'text/plain' })
+      const url = URL.createObjectURL(blob)
+      const a = document.createElement('a')
+      a.href = url
+      a.download = `session-${session.ticket_number || session.id}.${exportFormat === 'markdown' ? 'md' : exportFormat === 'html' ? 'html' : 'txt'}`
+      document.body.appendChild(a)
+      a.click()
+      document.body.removeChild(a)
+      URL.revokeObjectURL(url)
+    } catch (err) {
+      console.error('Export failed:', err)
+    } finally {
+      setIsExporting(false)
+    }
+  }
+
+  const formatDate = (dateString: string) => {
+    return new Date(dateString).toLocaleString()
+  }
+
+  if (isLoading) {
+    return (
+      <div className="flex h-64 items-center justify-center">
+        <div className="h-8 w-8 animate-spin rounded-full border-4 border-primary border-t-transparent" />
+      </div>
+    )
+  }
+
+  if (error || !session) {
+    return (
+      <div className="container mx-auto px-4 py-8">
+        <div className="rounded-md bg-destructive/10 p-4 text-destructive">
+          {error || 'Session not found'}
+        </div>
+        <button
+          onClick={() => navigate('/sessions')}
+          className="mt-4 text-primary hover:underline"
+        >
+          Back to sessions
+        </button>
+      </div>
+    )
+  }
+
+  return (
+    <div className="container mx-auto px-4 py-8">
+      {/* Header */}
+      <div className="mb-8 flex items-start justify-between">
+        <div>
+          <button
+            onClick={() => navigate('/sessions')}
+            className="mb-2 text-sm text-muted-foreground hover:text-foreground"
+          >
+            ← Back to sessions
+          </button>
+          <h1 className="text-3xl font-bold text-foreground">
+            {session.ticket_number || 'Session Details'}
+          </h1>
+          <div className="mt-2 flex items-center gap-4 text-sm text-muted-foreground">
+            <span
+              className={cn(
+                'flex items-center gap-1',
+                session.completed_at ? 'text-green-600' : 'text-yellow-600'
+              )}
+            >
+              <span
+                className={cn(
+                  'h-2 w-2 rounded-full',
+                  session.completed_at ? 'bg-green-500' : 'bg-yellow-500'
+                )}
+              />
+              {session.completed_at ? 'Completed' : 'In Progress'}
+            </span>
+            {session.client_name && <span>Client: {session.client_name}</span>}
+          </div>
+        </div>
+
+        {/* Export */}
+        <div className="flex items-center gap-2">
+          <select
+            value={exportFormat}
+            onChange={(e) => setExportFormat(e.target.value as typeof exportFormat)}
+            className={cn(
+              'rounded-md border border-input bg-background px-3 py-2 text-sm',
+              'focus:border-primary focus:outline-none focus:ring-1 focus:ring-primary'
+            )}
+          >
+            <option value="markdown">Markdown</option>
+            <option value="text">Plain Text</option>
+            <option value="html">HTML</option>
+          </select>
+          <button
+            onClick={handleExport}
+            disabled={isExporting}
+            className={cn(
+              'rounded-md bg-primary px-4 py-2 text-sm font-medium text-primary-foreground',
+              'hover:bg-primary/90 disabled:opacity-50'
+            )}
+          >
+            {isExporting ? 'Exporting...' : 'Export'}
+          </button>
+        </div>
+      </div>
+
+      {/* Timeline */}
+      <div className="mb-8">
+        <h2 className="mb-4 text-lg font-semibold text-foreground">Decision Timeline</h2>
+        <div className="space-y-4">
+          <div className="flex items-center gap-3 text-sm">
+            <span className="h-3 w-3 rounded-full bg-primary" />
+            <span className="text-muted-foreground">
+              Session started: {formatDate(session.started_at)}
+            </span>
+          </div>
+
+          {session.decisions.map((decision, index) => (
+            <div key={index} className="ml-1 border-l-2 border-border pl-6">
+              <div className="relative">
+                <span className="absolute -left-[1.625rem] top-1 h-2 w-2 rounded-full bg-border" />
+                <div className="rounded-lg border border-border bg-card p-4">
+                  {decision.question && (
+                    <p className="font-medium text-card-foreground">{decision.question}</p>
+                  )}
+                  {decision.answer && (
+                    <p className="mt-1 text-sm text-primary">Answer: {decision.answer}</p>
+                  )}
+                  {decision.action_performed && (
+                    <p className="mt-1 text-sm text-muted-foreground">
+                      Action: {decision.action_performed}
+                    </p>
+                  )}
+                  {decision.notes && (
+                    <p className="mt-2 rounded bg-muted/50 p-2 text-sm text-muted-foreground">
+                      Notes: {decision.notes}
+                    </p>
+                  )}
+                  <p className="mt-2 text-xs text-muted-foreground">
+                    {formatDate(decision.timestamp)}
+                  </p>
+                </div>
+              </div>
+            </div>
+          ))}
+
+          {session.completed_at && (
+            <div className="flex items-center gap-3 text-sm">
+              <span className="h-3 w-3 rounded-full bg-green-500" />
+              <span className="text-green-600">
+                Session completed: {formatDate(session.completed_at)}
+              </span>
+            </div>
+          )}
+        </div>
+      </div>
+    </div>
+  )
+}
+
+export default SessionDetailPage
--- a/frontend/src/pages/SessionHistoryPage.tsx
+++ b/frontend/src/pages/SessionHistoryPage.tsx
@@ -0,0 +1,152 @@
+import { useEffect, useState } from 'react'
+import { useNavigate } from 'react-router-dom'
+import { sessionsApi } from '@/api'
+import type { Session } from '@/types'
+import { cn } from '@/lib/utils'
+
+export function SessionHistoryPage() {
+  const navigate = useNavigate()
+  const [sessions, setSessions] = useState<Session[]>([])
+  const [isLoading, setIsLoading] = useState(true)
+  const [error, setError] = useState<string | null>(null)
+  const [filter, setFilter] = useState<'all' | 'completed' | 'active'>('all')
+
+  useEffect(() => {
+    loadSessions()
+  }, [filter])
+
+  const loadSessions = async () => {
+    setIsLoading(true)
+    setError(null)
+    try {
+      const params = filter === 'all' ? {} : { completed: filter === 'completed' }
+      const sessionsData = await sessionsApi.list(params)
+      setSessions(sessionsData)
+    } catch (err) {
+      setError('Failed to load sessions')
+      console.error(err)
+    } finally {
+      setIsLoading(false)
+    }
+  }
+
+  const formatDate = (dateString: string) => {
+    return new Date(dateString).toLocaleString()
+  }
+
+  return (
+    <div className="container mx-auto px-4 py-8">
+      <div className="mb-8">
+        <h1 className="text-3xl font-bold text-foreground">Session History</h1>
+        <p className="mt-2 text-muted-foreground">
+          View and manage your troubleshooting sessions
+        </p>
+      </div>
+
+      {/* Filter Tabs */}
+      <div className="mb-6 flex gap-2 border-b border-border">
+        {(['all', 'active', 'completed'] as const).map((tab) => (
+          <button
+            key={tab}
+            onClick={() => setFilter(tab)}
+            className={cn(
+              'px-4 py-2 text-sm font-medium transition-colors',
+              filter === tab
+                ? 'border-b-2 border-primary text-primary'
+                : 'text-muted-foreground hover:text-foreground'
+            )}
+          >
+            {tab.charAt(0).toUpperCase() + tab.slice(1)}
+          </button>
+        ))}
+      </div>
+
+      {/* Error State */}
+      {error && (
+        <div className="mb-6 rounded-md bg-destructive/10 p-4 text-destructive">
+          {error}
+        </div>
+      )}
+
+      {/* Loading State */}
+      {isLoading ? (
+        <div className="flex justify-center py-12">
+          <div className="h-8 w-8 animate-spin rounded-full border-4 border-primary border-t-transparent" />
+        </div>
+      ) : sessions.length === 0 ? (
+        <div className="py-12 text-center text-muted-foreground">
+          No sessions found.{' '}
+          <button
+            onClick={() => navigate('/trees')}
+            className="text-primary hover:underline"
+          >
+            Start a new session
+          </button>
+        </div>
+      ) : (
+        <div className="space-y-4">
+          {sessions.map((session) => (
+            <div
+              key={session.id}
+              className="rounded-lg border border-border bg-card p-4 shadow-sm transition-shadow hover:shadow-md"
+            >
+              <div className="flex items-start justify-between">
+                <div>
+                  <div className="flex items-center gap-2">
+                    <span
+                      className={cn(
+                        'inline-block h-2 w-2 rounded-full',
+                        session.completed_at ? 'bg-green-500' : 'bg-yellow-500'
+                      )}
+                    />
+                    <span className="font-medium text-card-foreground">
+                      {session.ticket_number || 'No ticket'}
+                    </span>
+                    {session.client_name && (
+                      <span className="text-muted-foreground">
+                        · {session.client_name}
+                      </span>
+                    )}
+                  </div>
+                  <p className="mt-1 text-sm text-muted-foreground">
+                    Started: {formatDate(session.started_at)}
+                    {session.completed_at && (
+                      <> · Completed: {formatDate(session.completed_at)}</>
+                    )}
+                  </p>
+                  <p className="mt-1 text-sm text-muted-foreground">
+                    {session.decisions.length} decisions recorded
+                  </p>
+                </div>
+                <div className="flex gap-2">
+                  <button
+                    onClick={() => navigate(`/sessions/${session.id}`)}
+                    className={cn(
+                      'rounded-md border border-input px-3 py-1.5 text-sm font-medium',
+                      'hover:bg-accent hover:text-accent-foreground'
+                    )}
+                  >
+                    View Details
+                  </button>
+                  {!session.completed_at && (
+                    <button
+                      onClick={() => navigate(`/trees/${session.tree_id}/navigate`, { state: { sessionId: session.id } })}
+                      className={cn(
+                        'rounded-md bg-primary px-3 py-1.5 text-sm font-medium text-primary-foreground',
+                        'hover:bg-primary/90'
+                      )}
+                    >
+                      Resume
+                    </button>
+                  )}
+                </div>
+              </div>
+            </div>
+          ))}
+        </div>
+      )}
+    </div>
+  )
+}
+
+export default SessionHistoryPage
--- a/frontend/src/pages/TreeLibraryPage.tsx
+++ b/frontend/src/pages/TreeLibraryPage.tsx
@@ -0,0 +1,168 @@
+import { useEffect, useState } from 'react'
+import { useNavigate } from 'react-router-dom'
+import { treesApi } from '@/api'
+import type { TreeListItem } from '@/types'
+import { cn } from '@/lib/utils'
+
+export function TreeLibraryPage() {
+  const navigate = useNavigate()
+  const [trees, setTrees] = useState<TreeListItem[]>([])
+  const [categories, setCategories] = useState<string[]>([])
+  const [selectedCategory, setSelectedCategory] = useState<string>('')
+  const [searchQuery, setSearchQuery] = useState('')
+  const [isLoading, setIsLoading] = useState(true)
+  const [error, setError] = useState<string | null>(null)
+
+  useEffect(() => {
+    loadData()
+  }, [selectedCategory])
+
+  const loadData = async () => {
+    setIsLoading(true)
+    setError(null)
+    try {
+      const [treesData, categoriesData] = await Promise.all([
+        treesApi.list({ category: selectedCategory || undefined }),
+        treesApi.categories(),
+      ])
+      setTrees(treesData)
+      setCategories(categoriesData)
+    } catch (err) {
+      setError('Failed to load trees')
+      console.error(err)
+    } finally {
+      setIsLoading(false)
+    }
+  }
+
+  const handleSearch = async () => {
+    if (!searchQuery.trim()) {
+      loadData()
+      return
+    }
+    setIsLoading(true)
+    setError(null)
+    try {
+      const results = await treesApi.search(searchQuery, selectedCategory || undefined)
+      setTrees(results)
+    } catch (err) {
+      setError('Search failed')
+      console.error(err)
+    } finally {
+      setIsLoading(false)
+    }
+  }
+
+  const handleStartSession = (treeId: string) => {
+    navigate(`/trees/${treeId}/navigate`)
+  }
+
+  return (
+    <div className="container mx-auto px-4 py-8">
+      <div className="mb-8">
+        <h1 className="text-3xl font-bold text-foreground">Decision Trees</h1>
+        <p className="mt-2 text-muted-foreground">
+          Select a troubleshooting tree to start a new session
+        </p>
+      </div>
+
+      {/* Search and Filter */}
+      <div className="mb-6 flex flex-col gap-4 sm:flex-row">
+        <div className="flex flex-1 gap-2">
+          <input
+            type="text"
+            placeholder="Search trees..."
+            value={searchQuery}
+            onChange={(e) => setSearchQuery(e.target.value)}
+            onKeyDown={(e) => e.key === 'Enter' && handleSearch()}
+            className={cn(
+              'flex-1 rounded-md border border-input bg-background px-3 py-2',
+              'text-foreground placeholder:text-muted-foreground',
+              'focus:border-primary focus:outline-none focus:ring-1 focus:ring-primary'
+            )}
+          />
+          <button
+            onClick={handleSearch}
+            className={cn(
+              'rounded-md bg-primary px-4 py-2 text-sm font-medium text-primary-foreground',
+              'hover:bg-primary/90'
+            )}
+          >
+            Search
+          </button>
+        </div>
+
+        <select
+          value={selectedCategory}
+          onChange={(e) => setSelectedCategory(e.target.value)}
+          className={cn(
+            'rounded-md border border-input bg-background px-3 py-2',
+            'text-foreground focus:border-primary focus:outline-none focus:ring-1 focus:ring-primary'
+          )}
+        >
+          <option value="">All Categories</option>
+          {categories.map((cat) => (
+            <option key={cat} value={cat}>
+              {cat}
+            </option>
+          ))}
+        </select>
+      </div>
+
+      {/* Error State */}
+      {error && (
+        <div className="mb-6 rounded-md bg-destructive/10 p-4 text-destructive">
+          {error}
+        </div>
+      )}
+
+      {/* Loading State */}
+      {isLoading ? (
+        <div className="flex justify-center py-12">
+          <div className="h-8 w-8 animate-spin rounded-full border-4 border-primary border-t-transparent" />
+        </div>
+      ) : trees.length === 0 ? (
+        <div className="py-12 text-center text-muted-foreground">
+          No trees found. {searchQuery && 'Try adjusting your search.'}
+        </div>
+      ) : (
+        <div className="grid gap-4 sm:grid-cols-2 lg:grid-cols-3">
+          {trees.map((tree) => (
+            <div
+              key={tree.id}
+              className="rounded-lg border border-border bg-card p-6 shadow-sm transition-shadow hover:shadow-md"
+            >
+              <div className="mb-2 flex items-start justify-between">
+                <h3 className="font-semibold text-card-foreground">{tree.name}</h3>
+                {tree.category && (
+                  <span className="rounded-full bg-secondary px-2 py-0.5 text-xs text-secondary-foreground">
+                    {tree.category}
+                  </span>
+                )}
+              </div>
+              <p className="mb-4 text-sm text-muted-foreground line-clamp-2">
+                {tree.description || 'No description available'}
+              </p>
+              <div className="flex items-center justify-between">
+                <span className="text-xs text-muted-foreground">
+                  v{tree.version} · {tree.usage_count} uses
+                </span>
+                <button
+                  onClick={() => handleStartSession(tree.id)}
+                  className={cn(
+                    'rounded-md bg-primary px-3 py-1.5 text-sm font-medium text-primary-foreground',
+                    'hover:bg-primary/90'
+                  )}
+                >
+                  Start Session
+                </button>
+              </div>
+            </div>
+          ))}
+        </div>
+      )}
+    </div>
+  )
+}
+
+export default TreeLibraryPage
--- a/frontend/src/pages/TreeNavigationPage.tsx
+++ b/frontend/src/pages/TreeNavigationPage.tsx
@@ -0,0 +1,484 @@
+import { useEffect, useState } from 'react'
+import { useParams, useNavigate, useLocation } from 'react-router-dom'
+import { treesApi, sessionsApi } from '@/api'
+import type { Tree, Session, DecisionRecord, TreeStructure } from '@/types'
+import { cn } from '@/lib/utils'
+
+interface LocationState {
+  sessionId?: string
+}
+
+export function TreeNavigationPage() {
+  const { id: treeId } = useParams<{ id: string }>()
+  const navigate = useNavigate()
+  const location = useLocation()
+  const locationState = location.state as LocationState | undefined
+
+  const [tree, setTree] = useState<Tree | null>(null)
+  const [session, setSession] = useState<Session | null>(null)
+  const [currentNodeId, setCurrentNodeId] = useState<string>('root')
+  const [pathTaken, setPathTaken] = useState<string[]>(['root'])
+  const [decisions, setDecisions] = useState<DecisionRecord[]>([])
+  const [notes, setNotes] = useState<string>('')
+  const [isLoading, setIsLoading] = useState(true)
+  const [error, setError] = useState<string | null>(null)
+  const [isCompleting, setIsCompleting] = useState(false)
+
+  // Session metadata
+  const [ticketNumber, setTicketNumber] = useState<string>('')
+  const [clientName, setClientName] = useState<string>('')
+  const [showMetadataForm, setShowMetadataForm] = useState(true)
+
+  useEffect(() => {
+    if (treeId) {
+      loadTreeAndSession()
+    }
+  }, [treeId])
+
+  const loadTreeAndSession = async () => {
+    setIsLoading(true)
+    setError(null)
+    try {
+      const treeData = await treesApi.get(treeId!)
+      setTree(treeData)
+
+      // If resuming a session
+      if (locationState?.sessionId) {
+        const sessionData = await sessionsApi.get(locationState.sessionId)
+        setSession(sessionData)
+        setPathTaken(sessionData.path_taken)
+        setCurrentNodeId(sessionData.path_taken[sessionData.path_taken.length - 1] || 'root')
+        setDecisions(sessionData.decisions as DecisionRecord[])
+        setTicketNumber(sessionData.ticket_number || '')
+        setClientName(sessionData.client_name || '')
+        setShowMetadataForm(false)
+      }
+    } catch (err) {
+      setError('Failed to load tree')
+      console.error(err)
+    } finally {
+      setIsLoading(false)
+    }
+  }
+
+  const startSession = async () => {
+    if (!tree) return
+    setIsLoading(true)
+    try {
+      const newSession = await sessionsApi.create({
+        tree_id: tree.id,
+        ticket_number: ticketNumber || undefined,
+        client_name: clientName || undefined,
+      })
+      setSession(newSession)
+      setShowMetadataForm(false)
+    } catch (err) {
+      setError('Failed to start session')
+      console.error(err)
+    } finally {
+      setIsLoading(false)
+    }
+  }
+
+  const findNode = (nodeId: string, structure: TreeStructure = tree?.tree_structure!): TreeStructure | null => {
+    if (structure.id === nodeId) return structure
+    if (structure.children) {
+      for (const child of structure.children) {
+        const found = findNode(nodeId, child)
+        if (found) return found
+      }
+    }
+    return null
+  }
+
+  const handleSelectOption = async (_optionId: string, optionLabel: string, nextNodeId: string) => {
+    if (!session || !tree) return
+
+    const currentNode = findNode(currentNodeId)
+    if (!currentNode) return
+
+    const newDecision: DecisionRecord = {
+      node_id: currentNodeId,
+      question: currentNode.question || null,
+      answer: optionLabel,
+      action_performed: null,
+      notes: notes || null,
+      automation_used: false,
+      timestamp: new Date().toISOString(),
+      attachments: [],
+    }
+
+    const newPath = [...pathTaken, nextNodeId]
+    const newDecisions = [...decisions, newDecision]
+
+    setPathTaken(newPath)
+    setDecisions(newDecisions)
+    setCurrentNodeId(nextNodeId)
+    setNotes('')
+
+    // Update session on backend
+    try {
+      await sessionsApi.update(session.id, {
+        path_taken: newPath,
+        decisions: newDecisions,
+      })
+    } catch (err) {
+      console.error('Failed to update session:', err)
+    }
+  }
+
+  const handleContinue = async (actionPerformed?: string) => {
+    if (!session || !tree) return
+
+    const currentNode = findNode(currentNodeId)
+    if (!currentNode || !currentNode.next_node_id) return
+
+    const newDecision: DecisionRecord = {
+      node_id: currentNodeId,
+      question: null,
+      answer: null,
+      action_performed: actionPerformed || currentNode.title || 'Action completed',
+      notes: notes || null,
+      automation_used: false,
+      timestamp: new Date().toISOString(),
+      attachments: [],
+    }
+
+    const newPath = [...pathTaken, currentNode.next_node_id]
+    const newDecisions = [...decisions, newDecision]
+
+    setPathTaken(newPath)
+    setDecisions(newDecisions)
+    setCurrentNodeId(currentNode.next_node_id)
+    setNotes('')
+
+    try {
+      await sessionsApi.update(session.id, {
+        path_taken: newPath,
+        decisions: newDecisions,
+      })
+    } catch (err) {
+      console.error('Failed to update session:', err)
+    }
+  }
+
+  const handleComplete = async () => {
+    if (!session) return
+    setIsCompleting(true)
+    setError(null)
+    try {
+      // Add final decision
+      const currentNode = findNode(currentNodeId)
+      if (currentNode) {
+        const finalDecision: DecisionRecord = {
+          node_id: currentNodeId,
+          question: null,
+          answer: null,
+          action_performed: currentNode.title || 'Session completed',
+          notes: notes || null,
+          automation_used: false,
+          timestamp: new Date().toISOString(),
+          attachments: [],
+        }
+        await sessionsApi.update(session.id, {
+          decisions: [...decisions, finalDecision],
+        })
+      }
+
+      await sessionsApi.complete(session.id)
+      navigate(`/sessions/${session.id}`)
+    } catch (err) {
+      console.error('Failed to complete session:', err)
+      setError('Failed to complete session. Check console for details.')
+    } finally {
+      setIsCompleting(false)
+    }
+  }
+
+  const handleGoBack = () => {
+    if (pathTaken.length <= 1) return
+    const newPath = pathTaken.slice(0, -1)
+    const newDecisions = decisions.slice(0, -1)
+    setPathTaken(newPath)
+    setDecisions(newDecisions)
+    setCurrentNodeId(newPath[newPath.length - 1])
+  }
+
+  if (isLoading) {
+    return (
+      <div className="flex h-64 items-center justify-center">
+        <div className="h-8 w-8 animate-spin rounded-full border-4 border-primary border-t-transparent" />
+      </div>
+    )
+  }
+
+  if (error || !tree) {
+    return (
+      <div className="container mx-auto px-4 py-8">
+        <div className="rounded-md bg-destructive/10 p-4 text-destructive">
+          {error || 'Tree not found'}
+        </div>
+        <button
+          onClick={() => navigate('/trees')}
+          className="mt-4 text-primary hover:underline"
+        >
+          Back to trees
+        </button>
+      </div>
+    )
+  }
+
+  // Session metadata form
+  if (showMetadataForm) {
+    return (
+      <div className="container mx-auto max-w-lg px-4 py-8">
+        <h1 className="mb-2 text-2xl font-bold text-foreground">{tree.name}</h1>
+        <p className="mb-6 text-muted-foreground">{tree.description}</p>
+
+        <div className="space-y-4 rounded-lg border border-border bg-card p-6">
+          <h2 className="font-semibold text-card-foreground">Session Details</h2>
+          <p className="text-sm text-muted-foreground">
+            Optional: Add ticket and client info for easier tracking
+          </p>
+
+          <div>
+            <label className="block text-sm font-medium text-foreground">
+              Ticket Number
+            </label>
+            <input
+              type="text"
+              value={ticketNumber}
+              onChange={(e) => setTicketNumber(e.target.value)}
+              placeholder="e.g., INC0012345"
+              className={cn(
+                'mt-1 block w-full rounded-md border border-input bg-background px-3 py-2',
+                'text-foreground placeholder:text-muted-foreground',
+                'focus:border-primary focus:outline-none focus:ring-1 focus:ring-primary'
+              )}
+            />
+          </div>
+
+          <div>
+            <label className="block text-sm font-medium text-foreground">
+              Client Name
+            </label>
+            <input
+              type="text"
+              value={clientName}
+              onChange={(e) => setClientName(e.target.value)}
+              placeholder="e.g., Acme Corp"
+              className={cn(
+                'mt-1 block w-full rounded-md border border-input bg-background px-3 py-2',
+                'text-foreground placeholder:text-muted-foreground',
+                'focus:border-primary focus:outline-none focus:ring-1 focus:ring-primary'
+              )}
+            />
+          </div>
+
+          <button
+            onClick={startSession}
+            className={cn(
+              'w-full rounded-md bg-primary px-4 py-2 text-sm font-medium text-primary-foreground',
+              'hover:bg-primary/90'
+            )}
+          >
+            Start Troubleshooting
+          </button>
+        </div>
+      </div>
+    )
+  }
+
+  const currentNode = findNode(currentNodeId)
+
+  if (!currentNode) {
+    return (
+      <div className="container mx-auto px-4 py-8">
+        <div className="rounded-md bg-destructive/10 p-4 text-destructive">
+          Invalid tree structure
+        </div>
+      </div>
+    )
+  }
+
+  return (
+    <div className="container mx-auto px-4 py-8">
+      {/* Header */}
+      <div className="mb-6 flex items-center justify-between">
+        <div>
+          <h1 className="text-xl font-bold text-foreground">{tree.name}</h1>
+          {(ticketNumber || clientName) && (
+            <p className="text-sm text-muted-foreground">
+              {ticketNumber && `Ticket: ${ticketNumber}`}
+              {ticketNumber && clientName && ' · '}
+              {clientName && `Client: ${clientName}`}
+            </p>
+          )}
+        </div>
+        <button
+          onClick={() => navigate('/sessions')}
+          className="text-sm text-muted-foreground hover:text-foreground"
+        >
+          Exit
+        </button>
+      </div>
+
+      {/* Breadcrumb */}
+      <div className="mb-6 flex items-center gap-2 overflow-x-auto text-sm">
+        {pathTaken.map((nodeId, index) => {
+          const node = findNode(nodeId)
+          return (
+            <span key={nodeId} className="flex items-center gap-2 whitespace-nowrap">
+              {index > 0 && <span className="text-muted-foreground">→</span>}
+              <span
+                className={cn(
+                  index === pathTaken.length - 1
+                    ? 'font-medium text-foreground'
+                    : 'text-muted-foreground'
+                )}
+              >
+                {node?.question?.slice(0, 30) || node?.title?.slice(0, 30) || nodeId}
+                {((node?.question?.length || 0) > 30 || (node?.title?.length || 0) > 30) && '...'}
+              </span>
+            </span>
+          )
+        })}
+      </div>
+
+      {/* Current Node */}
+      <div className="rounded-lg border border-border bg-card p-6 shadow-sm">
+        {/* Decision Node */}
+        {currentNode.type === 'decision' && (
+          <>
+            <h2 className="mb-2 text-xl font-semibold text-card-foreground">
+              {currentNode.question}
+            </h2>
+            {currentNode.help_text && (
+              <p className="mb-4 text-sm text-muted-foreground">{currentNode.help_text}</p>
+            )}
+            <div className="mb-4 space-y-2">
+              {currentNode.options?.map((option) => (
+                <button
+                  key={option.id}
+                  onClick={() => handleSelectOption(option.id, option.label, option.next_node_id)}
+                  className={cn(
+                    'w-full rounded-md border border-input p-3 text-left transition-colors',
+                    'hover:border-primary hover:bg-accent'
+                  )}
+                >
+                  {option.label}
+                </button>
+              ))}
+            </div>
+          </>
+        )}
+
+        {/* Action Node */}
+        {currentNode.type === 'action' && (
+          <>
+            <h2 className="mb-2 text-xl font-semibold text-card-foreground">
+              {currentNode.title}
+            </h2>
+            <p className="mb-4 text-muted-foreground">{currentNode.description}</p>
+            {currentNode.commands && currentNode.commands.length > 0 && (
+              <div className="mb-4">
+                <p className="mb-2 text-sm font-medium text-foreground">Commands:</p>
+                <div className="space-y-1">
+                  {currentNode.commands.map((cmd, index) => (
+                    <code
+                      key={index}
+                      className="block rounded bg-muted p-2 text-sm font-mono"
+                    >
+                      {cmd}
+                    </code>
+                  ))}
+                </div>
+              </div>
+            )}
+            {currentNode.expected_outcome && (
+              <p className="mb-4 text-sm text-muted-foreground">
+                <strong>Expected outcome:</strong> {currentNode.expected_outcome}
+              </p>
+            )}
+            {currentNode.next_node_id && (
+              <button
+                onClick={() => handleContinue()}
+                className={cn(
+                  'rounded-md bg-primary px-4 py-2 text-sm font-medium text-primary-foreground',
+                  'hover:bg-primary/90'
+                )}
+              >
+                Continue
+              </button>
+            )}
+          </>
+        )}
+
+        {/* Solution Node */}
+        {currentNode.type === 'solution' && (
+          <>
+            <div className="mb-4 flex items-center gap-2">
+              <span className="rounded-full bg-green-100 px-2 py-1 text-xs font-medium text-green-800">
+                Solution
+              </span>
+            </div>
+            <h2 className="mb-2 text-xl font-semibold text-card-foreground">
+              {currentNode.title}
+            </h2>
+            <p className="mb-4 text-muted-foreground">{currentNode.description}</p>
+            {currentNode.resolution_steps && currentNode.resolution_steps.length > 0 && (
+              <div className="mb-4">
+                <p className="mb-2 text-sm font-medium text-foreground">Resolution steps:</p>
+                <ol className="list-inside list-decimal space-y-1 text-sm text-muted-foreground">
+                  {currentNode.resolution_steps.map((step, index) => (
+                    <li key={index}>{step}</li>
+                  ))}
+                </ol>
+              </div>
+            )}
+            <button
+              onClick={handleComplete}
+              disabled={isCompleting}
+              className={cn(
+                'rounded-md bg-green-600 px-4 py-2 text-sm font-medium text-white',
+                'hover:bg-green-700 disabled:opacity-50'
+              )}
+            >
+              {isCompleting ? 'Completing...' : 'Complete Session'}
+            </button>
+          </>
+        )}
+
+        {/* Notes */}
+        <div className="mt-6 border-t border-border pt-4">
+          <label className="block text-sm font-medium text-foreground">
+            Notes (optional)
+          </label>
+          <textarea
+            value={notes}
+            onChange={(e) => setNotes(e.target.value)}
+            placeholder="Add any notes for this step..."
+            rows={2}
+            className={cn(
+              'mt-1 block w-full rounded-md border border-input bg-background px-3 py-2',
+              'text-foreground placeholder:text-muted-foreground',
+              'focus:border-primary focus:outline-none focus:ring-1 focus:ring-primary'
+            )}
+          />
+        </div>
+
+        {/* Back Button */}
+        {pathTaken.length > 1 && (
+          <button
+            onClick={handleGoBack}
+            className="mt-4 text-sm text-muted-foreground hover:text-foreground"
+          >
+            ← Go back
+          </button>
+        )}
+      </div>
+    </div>
+  )
+}
+
+export default TreeNavigationPage
--- a/frontend/src/pages/index.ts
+++ b/frontend/src/pages/index.ts
@@ -0,0 +1,6 @@
+export { default as LoginPage } from './LoginPage'
+export { default as RegisterPage } from './RegisterPage'
+export { default as TreeLibraryPage } from './TreeLibraryPage'
+export { default as TreeNavigationPage } from './TreeNavigationPage'
+export { default as SessionHistoryPage } from './SessionHistoryPage'
+export { default as SessionDetailPage } from './SessionDetailPage'
--- a/frontend/src/router.tsx
+++ b/frontend/src/router.tsx
@@ -0,0 +1,57 @@
+import { createBrowserRouter, Navigate } from 'react-router-dom'
+import { AppLayout, ProtectedRoute } from '@/components/layout'
+import { RouteError } from '@/components/common/RouteError'
+import {
+  LoginPage,
+  RegisterPage,
+  TreeLibraryPage,
+  TreeNavigationPage,
+  SessionHistoryPage,
+  SessionDetailPage,
+} from '@/pages'
+
+export const router = createBrowserRouter([
+  {
+    path: '/login',
+    element: <LoginPage />,
+    errorElement: <RouteError />,
+  },
+  {
+    path: '/register',
+    element: <RegisterPage />,
+    errorElement: <RouteError />,
+  },
+  {
+    path: '/',
+    element: (
+      <ProtectedRoute>
+        <AppLayout />
+      </ProtectedRoute>
+    ),
+    errorElement: <RouteError />,
+    children: [
+      {
+        index: true,
+        element: <Navigate to="/trees" replace />,
+      },
+      {
+        path: 'trees',
+        element: <TreeLibraryPage />,
+      },
+      {
+        path: 'trees/:id/navigate',
+        element: <TreeNavigationPage />,
+      },
+      {
+        path: 'sessions',
+        element: <SessionHistoryPage />,
+      },
+      {
+        path: 'sessions/:id',
+        element: <SessionDetailPage />,
+      },
+    ],
+  },
+])
+
+export default router
--- a/frontend/src/store/authStore.ts
+++ b/frontend/src/store/authStore.ts
@@ -0,0 +1,101 @@
+import { create } from 'zustand'
+import { persist } from 'zustand/middleware'
+import type { User, Token, UserCreate, UserLogin } from '@/types'
+import { authApi } from '@/api'
+
+interface AuthState {
+  user: User | null
+  token: Token | null
+  isAuthenticated: boolean
+  isLoading: boolean
+  error: string | null
+
+  // Actions
+  login: (credentials: UserLogin) => Promise<void>
+  register: (data: UserCreate) => Promise<void>
+  logout: () => Promise<void>
+  fetchUser: () => Promise<void>
+  clearError: () => void
+  setLoading: (loading: boolean) => void
+}
+
+export const useAuthStore = create<AuthState>()(
+  persist(
+    (set, get) => ({
+      user: null,
+      token: null,
+      isAuthenticated: false,
+      isLoading: false,
+      error: null,
+
+      login: async (credentials: UserLogin) => {
+        set({ isLoading: true, error: null })
+        try {
+          const token = await authApi.login(credentials)
+
+          // Store tokens
+          localStorage.setItem('access_token', token.access_token)
+          localStorage.setItem('refresh_token', token.refresh_token)
+
+          set({ token, isAuthenticated: true })
+
+          // Fetch user info
+          await get().fetchUser()
+        } catch (error: unknown) {
+          const message = error instanceof Error ? error.message : 'Login failed'
+          set({ error: message, isLoading: false })
+          throw error
+        }
+      },
+
+      register: async (data: UserCreate) => {
+        set({ isLoading: true, error: null })
+        try {
+          await authApi.register(data)
+          // After registration, log the user in
+          await get().login({ email: data.email, password: data.password })
+        } catch (error: unknown) {
+          const message = error instanceof Error ? error.message : 'Registration failed'
+          set({ error: message, isLoading: false })
+          throw error
+        }
+      },
+
+      logout: async () => {
+        try {
+          await authApi.logout()
+        } catch {
+          // Ignore logout errors
+        } finally {
+          localStorage.removeItem('access_token')
+          localStorage.removeItem('refresh_token')
+          set({ user: null, token: null, isAuthenticated: false, error: null })
+        }
+      },
+
+      fetchUser: async () => {
+        set({ isLoading: true })
+        try {
+          const user = await authApi.me()
+          set({ user, isLoading: false })
+        } catch (error: unknown) {
+          const message = error instanceof Error ? error.message : 'Failed to fetch user'
+          set({ error: message, isLoading: false })
+          throw error
+        }
+      },
+
+      clearError: () => set({ error: null }),
+      setLoading: (loading: boolean) => set({ isLoading: loading }),
+    }),
+    {
+      name: 'auth-storage',
+      partialize: (state) => ({
+        token: state.token,
+        isAuthenticated: state.isAuthenticated,
+      }),
+    }
+  )
+)
+
+export default useAuthStore
--- a/frontend/src/types/auth.ts
+++ b/frontend/src/types/auth.ts
@@ -0,0 +1,12 @@
+export interface Token {
+  access_token: string
+  refresh_token: string
+  token_type: string
+}
+
+export interface AuthState {
+  user: import('./user').User | null
+  token: Token | null
+  isAuthenticated: boolean
+  isLoading: boolean
+}
--- a/frontend/src/types/index.ts
+++ b/frontend/src/types/index.ts
@@ -0,0 +1,17 @@
+export * from './user'
+export * from './auth'
+export * from './tree'
+export * from './session'
+
+// API response wrapper types
+export interface PaginatedResponse<T> {
+  items: T[]
+  total: number
+  page: number
+  size: number
+  pages: number
+}
+
+export interface ApiError {
+  detail: string
+}
--- a/frontend/src/types/session.ts
+++ b/frontend/src/types/session.ts
@@ -0,0 +1,55 @@
+import type { TreeStructure } from './tree'
+
+export interface DecisionRecord {
+  node_id: string
+  question: string | null
+  answer: string | null
+  action_performed: string | null
+  notes: string | null
+  automation_used: boolean
+  timestamp: string
+  attachments: string[]
+}
+
+export interface Session {
+  id: string
+  tree_id: string
+  user_id: string
+  tree_snapshot: TreeStructure
+  path_taken: string[]
+  decisions: DecisionRecord[]
+  started_at: string
+  completed_at: string | null
+  ticket_number: string | null
+  client_name: string | null
+  exported: boolean
+}
+
+export interface SessionCreate {
+  tree_id: string
+  ticket_number?: string
+  client_name?: string
+}
+
+export interface SessionUpdate {
+  path_taken?: string[]
+  decisions?: DecisionRecord[]
+  ticket_number?: string
+  client_name?: string
+}
+
+export interface SessionExport {
+  format: 'text' | 'markdown' | 'html'
+  include_timestamps?: boolean
+  include_tree_info?: boolean
+}
+
+// Navigation state for active session
+export interface SessionNavigationState {
+  activeSession: Session | null
+  currentNodeId: string
+  pathTaken: string[]
+  decisions: DecisionRecord[]
+  isLoading: boolean
+  error: string | null
+}
--- a/frontend/src/types/tree.ts
+++ b/frontend/src/types/tree.ts
@@ -0,0 +1,98 @@
+// Tree node types
+export type NodeType = 'decision' | 'action' | 'solution'
+
+export interface TreeOption {
+  id: string
+  label: string
+  next_node_id: string
+}
+
+export interface TreeNodeBase {
+  id: string
+  type: NodeType
+}
+
+export interface DecisionNode extends TreeNodeBase {
+  type: 'decision'
+  question: string
+  help_text?: string
+  options: TreeOption[]
+  children: TreeNode[]
+}
+
+export interface ActionNode extends TreeNodeBase {
+  type: 'action'
+  title: string
+  description: string
+  commands?: string[]
+  expected_outcome?: string
+  next_node_id?: string
+  children?: TreeNode[]
+}
+
+export interface SolutionNode extends TreeNodeBase {
+  type: 'solution'
+  title: string
+  description: string
+  resolution_steps?: string[]
+}
+
+export type TreeNode = DecisionNode | ActionNode | SolutionNode
+
+export interface TreeStructure {
+  id: string
+  type: NodeType
+  question?: string
+  title?: string
+  description?: string
+  help_text?: string
+  options?: TreeOption[]
+  commands?: string[]
+  expected_outcome?: string
+  next_node_id?: string
+  resolution_steps?: string[]
+  children?: TreeStructure[]
+}
+
+// API response types
+export interface Tree {
+  id: string
+  name: string
+  description: string | null
+  category: string | null
+  tree_structure: TreeStructure
+  author_id: string | null
+  team_id: string | null
+  is_active: boolean
+  version: number
+  created_at: string
+  updated_at: string
+  usage_count: number
+}
+
+export interface TreeListItem {
+  id: string
+  name: string
+  description: string | null
+  category: string | null
+  is_active: boolean
+  version: number
+  usage_count: number
+  created_at: string
+  updated_at: string
+}
+
+export interface TreeCreate {
+  name: string
+  description?: string
+  category?: string
+  tree_structure: TreeStructure
+}
+
+export interface TreeUpdate {
+  name?: string
+  description?: string
+  category?: string
+  tree_structure?: TreeStructure
+  is_active?: boolean
+}
--- a/frontend/src/types/user.ts
+++ b/frontend/src/types/user.ts
@@ -0,0 +1,28 @@
+export type UserRole = 'admin' | 'engineer' | 'viewer'
+
+export interface User {
+  id: string
+  email: string
+  name: string
+  role: UserRole
+  team_id: string | null
+  created_at: string
+  last_login: string | null
+}
+
+export interface UserCreate {
+  email: string
+  password: string
+  name: string
+  role?: UserRole
+}
+
+export interface UserLogin {
+  email: string
+  password: string
+}
+
+export interface UserUpdate {
+  name?: string
+  email?: string
+}
--- a/frontend/tailwind.config.js
+++ b/frontend/tailwind.config.js
@@ -0,0 +1,53 @@
+/** @type {import('tailwindcss').Config} */
+export default {
+  darkMode: ["class"],
+  content: [
+    "./index.html",
+    "./src/**/*.{js,ts,jsx,tsx}",
+  ],
+  theme: {
+    extend: {
+      colors: {
+        border: "hsl(var(--border))",
+        input: "hsl(var(--input))",
+        ring: "hsl(var(--ring))",
+        background: "hsl(var(--background))",
+        foreground: "hsl(var(--foreground))",
+        primary: {
+          DEFAULT: "hsl(var(--primary))",
+          foreground: "hsl(var(--primary-foreground))",
+        },
+        secondary: {
+          DEFAULT: "hsl(var(--secondary))",
+          foreground: "hsl(var(--secondary-foreground))",
+        },
+        destructive: {
+          DEFAULT: "hsl(var(--destructive))",
+          foreground: "hsl(var(--destructive-foreground))",
+        },
+        muted: {
+          DEFAULT: "hsl(var(--muted))",
+          foreground: "hsl(var(--muted-foreground))",
+        },
+        accent: {
+          DEFAULT: "hsl(var(--accent))",
+          foreground: "hsl(var(--accent-foreground))",
+        },
+        popover: {
+          DEFAULT: "hsl(var(--popover))",
+          foreground: "hsl(var(--popover-foreground))",
+        },
+        card: {
+          DEFAULT: "hsl(var(--card))",
+          foreground: "hsl(var(--card-foreground))",
+        },
+      },
+      borderRadius: {
+        lg: "var(--radius)",
+        md: "calc(var(--radius) - 2px)",
+        sm: "calc(var(--radius) - 4px)",
+      },
+    },
+  },
+  plugins: [],
+}
--- a/frontend/tsconfig.app.json
+++ b/frontend/tsconfig.app.json
@@ -0,0 +1,34 @@
+{
+  "compilerOptions": {
+    "tsBuildInfoFile": "./node_modules/.tmp/tsconfig.app.tsbuildinfo",
+    "target": "ES2022",
+    "useDefineForClassFields": true,
+    "lib": ["ES2022", "DOM", "DOM.Iterable"],
+    "module": "ESNext",
+    "types": ["vite/client"],
+    "skipLibCheck": true,
+
+    /* Bundler mode */
+    "moduleResolution": "bundler",
+    "allowImportingTsExtensions": true,
+    "verbatimModuleSyntax": true,
+    "moduleDetection": "force",
+    "noEmit": true,
+    "jsx": "react-jsx",
+
+    /* Linting */
+    "strict": true,
+    "noUnusedLocals": true,
+    "noUnusedParameters": true,
+    "erasableSyntaxOnly": true,
+    "noFallthroughCasesInSwitch": true,
+    "noUncheckedSideEffectImports": true,
+
+    /* Path aliases */
+    "baseUrl": ".",
+    "paths": {
+      "@/*": ["./src/*"]
+    }
+  },
+  "include": ["src"]
+}
--- a/frontend/tsconfig.json
+++ b/frontend/tsconfig.json
@@ -0,0 +1,7 @@
+{
+  "files": [],
+  "references": [
+    { "path": "./tsconfig.app.json" },
+    { "path": "./tsconfig.node.json" }
+  ]
+}
--- a/frontend/tsconfig.node.json
+++ b/frontend/tsconfig.node.json
@@ -0,0 +1,26 @@
+{
+  "compilerOptions": {
+    "tsBuildInfoFile": "./node_modules/.tmp/tsconfig.node.tsbuildinfo",
+    "target": "ES2023",
+    "lib": ["ES2023"],
+    "module": "ESNext",
+    "types": ["node"],
+    "skipLibCheck": true,
+
+    /* Bundler mode */
+    "moduleResolution": "bundler",
+    "allowImportingTsExtensions": true,
+    "verbatimModuleSyntax": true,
+    "moduleDetection": "force",
+    "noEmit": true,
+
+    /* Linting */
+    "strict": true,
+    "noUnusedLocals": true,
+    "noUnusedParameters": true,
+    "erasableSyntaxOnly": true,
+    "noFallthroughCasesInSwitch": true,
+    "noUncheckedSideEffectImports": true
+  },
+  "include": ["vite.config.ts"]
+}
--- a/frontend/vite.config.ts
+++ b/frontend/vite.config.ts
@@ -0,0 +1,13 @@
+import { defineConfig } from 'vite'
+import react from '@vitejs/plugin-react'
+import path from 'path'
+
+// https://vite.dev/config/
+export default defineConfig({
+  plugins: [react()],
+  resolve: {
+    alias: {
+      '@': path.resolve(__dirname, './src'),
+    },
+  },
+})
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