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>

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