feat: implement Iteration 1 — AI recipe recommendations

Backend:
- Add Groq LLM client (llama-3.3-70b) for recipe generation with JSON
  retry strategy (retries only on parse errors, not API errors)
- Add Pexels client for parallel photo search per recipe
- Add saved_recipes table (migration 004) with JSONB fields
- Add GET /recommendations endpoint (profile-aware prompt building)
- Add POST/GET/GET{id}/DELETE /saved-recipes CRUD endpoints
- Wire gemini, pexels, recommendation, savedrecipe packages in main.go

Flutter:
- Add Recipe, SavedRecipe models with json_serializable
- Add RecipeService (getRecommendations, getSavedRecipes, save, delete)
- Add RecommendationsNotifier and SavedRecipesNotifier (Riverpod)
- Add RecommendationsScreen with skeleton loading and refresh FAB
- Add RecipeDetailScreen (SliverAppBar, nutrition tooltip, steps with timer)
- Add SavedRecipesScreen with Dismissible swipe-to-delete and empty state
- Update RecipesScreen to TabBar (Recommendations / Saved)
- Add /recipe-detail route outside ShellRoute (no bottom nav)
- Extend ApiClient with getList() and deleteVoid()

Project:
- Add CLAUDE.md with English-only rule for comments and commit messages

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

client/lib/features/recipes/recipes_screen.dart

@@ -1,13 +1,52 @@
 import 'package:flutter/material.dart';
 
-class RecipesScreen extends StatelessWidget {
+import 'recommendations_screen.dart';
+import 'saved_recipes_screen.dart';
+
+/// Root screen for the Recipes tab — two sub-tabs: Recommendations and Saved.
+class RecipesScreen extends StatefulWidget {
   const RecipesScreen({super.key});
 
+  @override
+  State<RecipesScreen> createState() => _RecipesScreenState();
+}
+
+class _RecipesScreenState extends State<RecipesScreen>
+    with SingleTickerProviderStateMixin {
+  late final TabController _tabController;
+
+  @override
+  void initState() {
+    super.initState();
+    _tabController = TabController(length: 2, vsync: this);
+  }
+
+  @override
+  void dispose() {
+    _tabController.dispose();
+    super.dispose();
+  }
+
   @override
   Widget build(BuildContext context) {
     return Scaffold(
-      appBar: AppBar(title: const Text('Рецепты')),
-      body: const Center(child: Text('Раздел в разработке')),
+      appBar: AppBar(
+        title: const Text('Рецепты'),
+        bottom: TabBar(
+          controller: _tabController,
+          tabs: const [
+            Tab(text: 'Рекомендации'),
+            Tab(text: 'Сохранённые'),
+          ],
+        ),
+      ),
+      body: TabBarView(
+        controller: _tabController,
+        children: const [
+          RecommendationsScreen(),
+          SavedRecipesScreen(),
+        ],
+      ),
     );
   }
 }