- C1: Fix race condition in handleReset — await abandonSession before
starting new session to prevent store state corruption
- I1: Extract error messages from Axios response.data.detail instead of
generic error.message — users now see helpful backend messages (quota
limits, message caps, etc.)
- I2: Add isGenerating guard in generateTree store action to prevent
concurrent generation requests on double-click
- I3: Add isResponding guard in sendMessage to prevent concurrent sends
- M5: Remove redundant type casts on flowType
- M6: Add rate limiter to DELETE /sessions/{id} for consistency
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
- TypeScript types for chat session, messages, and responses
- API client module with all 6 endpoints
- Zustand store with session management, message sending, tree generation, import, resume
- 7 chat components: ChatMessage, ChatInput, ChatPanel, PhaseIndicator, ChatToolbar, EmptyPreview, StaticTreePreview
- AIChatBuilderPage with split-panel layout (60% chat / 40% preview)
- Route at /ai/chat with lazy loading
- "Build with AI" button on TreeLibraryPage
- Session resume via URL search params
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
