test: add Playwright e2e tests for new features and uncovered workflows

High priority (new PR #108 features):
- Command palette: open/close, search flows, page navigation, FlowPilot handoff
- Fallback branches: add in editor, execute in session runner
- Session-to-flow: verify button appears on completed session detail

Medium priority (existing features without coverage):
- Procedural session: intake form, step-through, completion
- Tree editor: troubleshooting and procedural editor load/edit/save
- FlowPilot chat: page load, new chat creation
- Admin panel: dashboard, user management, settings access

Also adds API helpers: createProceduralTree(), createProceduralTreeWithFallbacks()

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/e2e/fallback-branches.spec.ts

@@ -0,0 +1,94 @@
+import { expect, test } from '@playwright/test'
+import {
+  createAuthenticatedApiContext,
+  createProceduralTree,
+  createProceduralTreeWithFallbacks,
+  disposeApiContext,
+  uniqueName,
+} from './helpers/api'
+
+test.describe('fallback branches smoke tests', () => {
+  test('can add and remove fallback steps in the procedural editor', async ({ page }) => {
+    const api = await createAuthenticatedApiContext()
+    const tree = await createProceduralTree(api, {
+      name: uniqueName('PW Editor Fallback Flow'),
+    })
+
+    try {
+      // Navigate to the procedural editor
+      await page.goto(`/flows/${tree.id}/edit`)
+
+      // Wait for editor to load
+      await expect(page.getByText('Verify the server is reachable')).toBeVisible({ timeout: 10000 })
+
+      // Click on the first step to expand it
+      await page.getByText('Verify the server is reachable').click()
+
+      // Look for fallback branches section
+      const fallbackToggle = page.getByText(/Fallback branches/)
+      await expect(fallbackToggle).toBeVisible()
+
+      // Expand fallback section
+      await fallbackToggle.click()
+
+      // Add a fallback step
+      await page.getByText('Add fallback step').click()
+
+      // Should show a new fallback step input
+      const fallbackInput = page.getByPlaceholder('Fallback step title')
+      await expect(fallbackInput).toBeVisible()
+      await fallbackInput.fill('Try alternative ping method')
+
+      // Fill description
+      const descInput = page.getByPlaceholder('What to try instead...')
+      await expect(descInput).toBeVisible()
+      await descInput.fill('Use traceroute if ping fails')
+
+      // Fallback count should update
+      await expect(page.getByText(/Fallback branches \(1\)/)).toBeVisible()
+    } finally {
+      await disposeApiContext(api)
+    }
+  })
+
+  test('shows fallback steps during procedural session execution', async ({ page }) => {
+    const api = await createAuthenticatedApiContext()
+    const tree = await createProceduralTreeWithFallbacks(api, {
+      name: uniqueName('PW Runner Fallback Flow'),
+    })
+
+    try {
+      // Navigate to the procedural flow
+      await page.goto(`/flows/${tree.id}/navigate`)
+      await expect(page.getByRole('heading', { name: tree.name })).toBeVisible({ timeout: 10000 })
+
+      // Start the session (no intake form on this flow)
+      const startButton = page.getByRole('button', { name: /Start/ })
+      await startButton.click()
+
+      // Should see the first step
+      await expect(page.getByText('Clear the DNS cache')).toBeVisible({ timeout: 5000 })
+
+      // Should see "Didn't work?" toggle since step has fallback_steps
+      const didntWorkToggle = page.getByText("Didn't work?")
+      await expect(didntWorkToggle).toBeVisible()
+
+      // Expand fallback section
+      await didntWorkToggle.click()
+
+      // Should see fallback step options
+      await expect(page.getByText('Restart DNS Client service')).toBeVisible()
+      await expect(page.getByText('Check DNS server configuration')).toBeVisible()
+
+      // Mark a fallback as resolved
+      const thisWorked = page.getByRole('button', { name: 'This worked' }).first()
+      await expect(thisWorked).toBeVisible()
+      await thisWorked.click()
+
+      // Fallback step should show completed styling
+      await expect(page.locator('[class*="border-emerald"]').first()).toBeVisible()
+    } finally {
+      await disposeApiContext(api)
+    }
+  })
+})