docs: update TODO.md to mark recipe CRUD API tasks as complete

TODO.md

@@ -1,6 +1,6 @@
 # TODO — Recipe Manager
 
-**Last Updated:** 2026-03-23  
+**Last Updated:** 2026-03-24  
 **Current Milestone:** MVP (v0.1)
 
 ---
@@ -11,9 +11,9 @@
 - [x] Initialize Node.js backend: Create src/backend/, package.json with express, better-sqlite3, zod, vitest. Create src/backend/index.ts with "Hello World" server on port 3000. Verify: npm install && npm run dev (server starts). Commit as "feat(backend): initialize Node.js project with Express"
 - [x] Set up TypeScript: Create tsconfig.json (strict mode, ES2022, Node16 module resolution). Add build script to package.json. Verify: npm run build succeeds. Commit.
 - [x] Create SQLite schema: Create src/backend/db/schema.sql with recipes, tags, recipe_tags tables per ARCHITECTURE.md. Create src/backend/db/migrate.ts to apply schema using sql.js (see ADR-001). Verify: npm run migrate creates data/recipes.db. Commit.
-- [ ] Implement recipe CRUD API endpoints
-- [ ] Add Zod validation schemas
-- [ ] Write API integration tests
+- [x] Implement recipe CRUD API endpoints
+- [x] Add Zod validation schemas
+- [x] Write API integration tests
 
 ### Frontend Setup
 - [ ] Initialize React + Vite project
@@ -45,7 +45,22 @@
 
 ## ✅ Completed Tasks
 
-_(none yet)_
+### 2026-03-24
+- **Recipe CRUD API implementation** (commit e2599b8)
+  - Implemented GET /api/recipes (list with pagination & search)
+  - Implemented GET /api/recipes/:id (get single recipe)
+  - Implemented POST /api/recipes (create recipe)
+  - Implemented PUT /api/recipes/:id (update recipe)
+  - Implemented DELETE /api/recipes/:id (delete recipe)
+  - Added Zod validation schemas for all endpoints
+  - Created layered architecture (Routes → Services → Repositories)
+  - Wrote 16 integration tests (all passing)
+  - Database auto-save functionality
+
+### 2026-03-23
+- Backend initialization (Node.js + Express)
+- TypeScript setup with strict mode
+- SQLite schema creation with sql.js
 
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