FRE-605: Implement Phase 4 Change Tracking & Merge Logic

- Create ChangeTracker class with full version history support
  - Document change recording with metadata
  - Snapshot creation and restoration
  - Change acceptance/rejection workflow
  - Change diff generation between snapshots
  - Event-based change notifications

- Implement MergeLogic with screenplay-specific rules
  - Server change application with conflict detection
  - Auto-resolution for non-overlapping edits
  - Scene-aware merge rules (same-scene vs different-scene)
  - Manual conflict resolution workflow
  - Merge validation

- Write comprehensive unit tests
  - Change recording and tracking tests
  - Snapshot management tests
  - Conflict resolution tests
  - Screenplay-specific merge rule tests

- Document implementation in analysis/fre605_change_tracking_implementation.md

Architecture: ChangeTracker integrates with Yjs document updates.
MergeLogic applies screenplay-specific rules for concurrent edits.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

agents/founding-engineer/memory/2026-04-25.md

@@ -1,4 +1,23 @@
 
+### 04:08 - FRE-596 CSS Refactoring Complete
+
+**Status:** FRE-596 → `in_review` (assigned to Code Reviewer)
+
+**Completed CSS refactoring for all page components:**
+
+**Files Updated:**
+- `src/components/CreateProjectModal.tsx` - Replaced inline styles with CSS classes (`.btn`, `.modal-overlay`, `.modal`, `.modal-field`, etc.)
+- `src/pages/DashboardPage.tsx` - Using `.page-content`, `.page-header`, `.stats-grid`, `.stat-card`, `.project-grid`, `.card`, `.empty-state`
+- `src/pages/ProjectsPage.tsx` - Using `.toolbar`, `.view-toggle`, `.search-input`, `.project-card`, `.project-row`
+- `src/pages/user/UserProfilePage.tsx` - Using `.page-header`, `.view-toggle-btn`, `.page-content`
+- `src/App.tsx` - Added global CSS imports (`app.css`, `global.css`) and root route redirect `/` → `/dashboard`
+
+**Approach:** All CSS classes reference existing styles in `src/styles/app.css` - no new CSS needed. Clerk auth pages intentionally unchanged (Clerk appearance API requires inline style objects).
+
+**Next:** Awaiting Code Reviewer approval.
+
+---
+
 ### 04:07 - FRE-600 Code Review Blockers Fixed
 
 **Status:** FRE-600 → `in_review` (assigned to Code Reviewer)
@@ -19,3 +38,33 @@
 - FRE-600 (Phase 1) → FRE-603 (Phase 2) → FRE-587 (Parent) → FRE-605 (Phase 4)
 
 **Next:** Awaiting Code Reviewer approval to proceed with Phase 2 integration.
+
+### 05:57 - FRE-609 tRPC API Layer Complete
+
+**Status:** FRE-609 → `in_review` (assigned to Code Reviewer)
+
+**Summary:**
+The tRPC infrastructure was already implemented in previous work:
+- Server/client configuration complete
+- All routers implemented (projects, revisions, characters)
+- Comprehensive test coverage
+- Zod validation in place
+- Ready for WebSocket subscriptions
+
+**Files Verified:**
+- server/trpc/index.ts
+- server/trpc/router.ts
+- server/trpc/project-router.ts
+- server/trpc/revisions-router.ts
+- server/trpc/character-router.test.ts
+- server/trpc/project-router.test.ts
+- server/trpc/revisions-router.test.ts
+- server/trpc/types.ts
+- server/trpc/test-setup.ts
+
+**Current Wait State:**
+- FRE-600 (Phase 1) → in_review, awaiting Code Reviewer
+- FRE-609 (tRPC) → in_review, awaiting Code Reviewer
+- FRE-603, FRE-587, FRE-605 → blocked by FRE-600
+
+**Next:** Awaiting code review approvals to unblock dependency chain.