chore: mark US-008 complete in prd.json and update progress log

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

progress.txt

@@ -17,6 +17,27 @@
 
 ---
 
+## 2026-02-19 - US-008
+- What was implemented:
+  - Full `checkpointsRouter` replacing stubs in `src/main/router/index.ts`
+  - Full `notesRouter` replacing stubs in `src/main/router/index.ts`
+  - Added `checkpoints` and `notes` to the schema import
+  - `checkpoints.list`: optional `projectId` filter, ordered by `asc(checkpoints.date)`
+  - `checkpoints.create`: inserts with UUID, createdAt=Date.now(), defaults isAiSuggested/isApproved to 0
+  - `checkpoints.update`: partial set for title/date/isApproved
+  - `checkpoints.delete`: deletes by id, returns `{ success: true }`
+  - `notes.list`: returns `{ id, projectId, title, createdAt, updatedAt }` only — no content (performance)
+  - `notes.get`: returns full record or null via `.all()[0] ?? null` pattern
+  - `notes.create`: inserts with UUID, createdAt=updatedAt=Date.now()
+  - `notes.update`: partial set, always sets updatedAt=Date.now() regardless of which fields changed
+  - `notes.delete`: deletes by id, returns `{ success: true }`
+- Files changed: `src/main/router/index.ts`, `prd.json`, `progress.txt`
+- **Learnings for future iterations:**
+  - `notes.update` must always set `updatedAt` — build the set object with updatedAt outside the conditional block
+  - `notes.list` intentionally excludes `content` column for performance; use `notes.get` for full record
+  - `checkpoints.projectId` is `.notNull()` in schema (unlike tasks.projectId which is nullable) — no null coalescing needed
+---
+
 ## 2026-02-19 - US-003
 - What was implemented:
   - Installed: electron-trpc, @trpc/server, @trpc/client, @trpc/react-query, @tanstack/react-query, zod