Scaffold Spring Boot 4.0.5 project with domain packages

Maven project with Java 21. Dependencies: web, data-jpa, security,
validation, flyway, postgresql, springdoc-openapi 3.0.2.
Package-by-domain structure: auth, household, recipe, planning,
shopping, pantry, admin, common. JPA open-in-view disabled,
Hibernate ddl-auto=validate (Flyway owns the schema).

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

backend/src/main/java/com/recipeapp/BackendApplication.java

@@ -0,0 +1,13 @@
+package com.recipeapp;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class BackendApplication {
+
+	public static void main(String[] args) {
+		SpringApplication.run(BackendApplication.class, args);
+	}
+
+}