Implement Recipe, Planning, Shopping, Pantry, and Admin domains

Outside-in TDD for all 5 remaining domains (128 tests total):
- Recipe: CRUD, ingredients autocomplete/patch, tags, categories (27 tests)
- Planning: week plans, slots, confirm, suggestions, variety score, cooking logs (24 tests)
- Shopping: generate from plan, publish, check/add/remove items (15 tests)
- Pantry: CRUD with expiry sorting (11 tests)
- Admin: user management, password reset, audit logging (13 tests)

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

backend/src/main/java/com/recipeapp/recipe/dto/RecipeSummaryResponse.java

@@ -0,0 +1,13 @@
+package com.recipeapp.recipe.dto;
+
+import java.util.UUID;
+
+public record RecipeSummaryResponse(
+        UUID id,
+        String name,
+        short serves,
+        short cookTimeMin,
+        String effort,
+        boolean isChildFriendly,
+        String heroImageUrl
+) {}