feat: implement Iteration 4 — menu planning, shopping list, diary

Backend:
- Migrations 007 (menu_plans, menu_items, shopping_lists) and
  008 (meal_diary)
- gemini/menu.go: GenerateMenu — 7-day × 3-meal plan via one Groq call
- internal/menu: model, repository (GetByWeek, SaveMenuInTx,
  shopping list CRUD), handler (GET/PUT/DELETE /menu,
  POST /ai/generate-menu, shopping list endpoints)
- internal/diary: model, repository, handler (GET/POST/DELETE /diary)
- Increase server WriteTimeout to 120s for long AI calls
- api_client.go: add patch() and postList() helpers

Flutter:
- shared/models: menu.dart, shopping_item.dart, diary_entry.dart
- features/menu: menu_service.dart, menu_provider.dart
  (MenuNotifier, ShoppingListNotifier, DiaryNotifier with family)
- MenuScreen: 7-day view, week nav, skeleton on generation,
  generate FAB with confirmation dialog
- ShoppingListScreen: items by category, optimistic checkbox toggle
- DiaryScreen: daily entries with swipe-to-delete, add-entry sheet
- Router: /menu/shopping-list and /menu/diary routes

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

backend/cmd/server/main.go

@@ -13,8 +13,10 @@ import (
 	"github.com/food-ai/backend/internal/auth"
 	"github.com/food-ai/backend/internal/config"
 	"github.com/food-ai/backend/internal/database"
+	"github.com/food-ai/backend/internal/diary"
 	"github.com/food-ai/backend/internal/gemini"
 	"github.com/food-ai/backend/internal/ingredient"
+	"github.com/food-ai/backend/internal/menu"
 	"github.com/food-ai/backend/internal/middleware"
 	"github.com/food-ai/backend/internal/pexels"
 	"github.com/food-ai/backend/internal/product"
@@ -112,6 +114,14 @@ func run() error {
 	savedRecipeRepo := savedrecipe.NewRepository(pool)
 	savedRecipeHandler := savedrecipe.NewHandler(savedRecipeRepo)
 
+	// Menu domain
+	menuRepo := menu.NewRepository(pool)
+	menuHandler := menu.NewHandler(menuRepo, geminiClient, pexelsClient, userRepo, productRepo, savedRecipeRepo)
+
+	// Diary domain
+	diaryRepo := diary.NewRepository(pool)
+	diaryHandler := diary.NewHandler(diaryRepo)
+
 	// Router
 	router := server.NewRouter(
 		pool,
@@ -122,6 +132,8 @@ func run() error {
 		ingredientHandler,
 		productHandler,
 		recognitionHandler,
+		menuHandler,
+		diaryHandler,
 		authMW,
 		cfg.AllowedOrigins,
 	)
@@ -130,7 +142,7 @@ func run() error {
 		Addr:         fmt.Sprintf(":%d", cfg.Port),
 		Handler:      router,
 		ReadTimeout:  10 * time.Second,
-		WriteTimeout: 30 * time.Second,
+		WriteTimeout: 120 * time.Second, // menu generation can take ~60s
 		IdleTimeout:  60 * time.Second,
 	}