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/RecipeCreateRequest.java

@@ -0,0 +1,32 @@
+package com.recipeapp.recipe.dto;
+
+import jakarta.validation.Valid;
+import jakarta.validation.constraints.*;
+import java.math.BigDecimal;
+import java.util.List;
+import java.util.UUID;
+
+public record RecipeCreateRequest(
+        @NotBlank @Size(max = 200) String name,
+        @Min(1) @Max(20) short serves,
+        @Min(0) short cookTimeMin,
+        @NotBlank @Pattern(regexp = "easy|medium|hard") String effort,
+        boolean isChildFriendly,
+        @Size(max = 500) String heroImageUrl,
+        @NotEmpty @Valid List<IngredientEntry> ingredients,
+        @Valid List<StepEntry> steps,
+        @NotEmpty List<UUID> tagIds
+) {
+    public record IngredientEntry(
+            UUID ingredientId,
+            @Size(max = 200) String newIngredientName,
+            @NotNull @DecimalMin("0.01") BigDecimal quantity,
+            @NotBlank @Size(max = 20) String unit,
+            short sortOrder
+    ) {}
+
+    public record StepEntry(
+            @Min(1) short stepNumber,
+            @NotBlank String instruction
+    ) {}
+}