feat: Phase 3 - Habits + Projects CRUD API, frontend, completions, sections

Habits REST API:
- GET/POST /api/domains/[domainId]/habits (list with filters, create)
- GET/PATCH/DELETE /api/domains/[domainId]/habits/[id] (detail, update, soft delete)
- POST /api/domains/[domainId]/habits/[id]/complete (completion + streak calc)
- GET /api/domains/[domainId]/habits/[id]/completions (list with date range)
- POST/DELETE /api/domains/[domainId]/habits/[id]/tags

Projects REST API:
- GET/POST /api/domains/[domainId]/projects (list with task counts, create)
- GET/PATCH/DELETE /api/domains/[domainId]/projects/[id] (detail with sections/tasks, update, soft delete)

Sections REST API:
- GET/POST /api/domains/[domainId]/projects/[projectId]/sections (list, create)
- GET/PATCH/DELETE /api/domains/[domainId]/projects/[projectId]/sections/[id]

Frontend:
- Habits page: checklist view, difficulty badges, streak display, filter
- Habit create dialog: name, description, frequency, difficulty, goal, unit, reminder, mood toggle
- Habit completion dialog: value, mood (1-5 emoji), notes
- Calendar heatmap: 365-day grid, color by value, hover tooltip
- Projects page: grid of cards with progress bars, status badges, tags
- Project detail page: sections board, drag tasks between sections
- Project create dialog: name, description, status, color picker, target date
- Section dialog: name, kind (section/milestone), status, target date

Keyboard shortcuts: c h (new habit), c p (new project), c s (new section)

All write routes follow AGENTS.md contract (Drizzle + recordActivity + pg_notify).
Build, typecheck, and 15 new tests pass.

package.json

@@ -22,6 +22,7 @@
   },
   "devDependencies": {
     "@playwright/test": "^1.61.1",
+    "@swc/jest": "^0.2.39",
     "drizzle-kit": "^0.31.10",
     "tsx": "^4.23.1",
     "turbo": "^2.5.0",