refactor: complete backend directory flattening

src/test/java/com/label/unit/PackageStructureMigrationTest.java

@@ -98,6 +98,33 @@ class PackageStructureMigrationTest {
         }
     }
 
+    @Test
+    @DisplayName("源码中不再引用 legacy module 与 common 目录包名")
+    void sourceTreeHasNoLegacyPackageReferences() throws Exception {
+        java.nio.file.Path self = java.nio.file.Path.of(
+                "src", "test", "java", "com", "label", "unit", "PackageStructureMigrationTest.java");
+        try (java.util.stream.Stream<java.nio.file.Path> paths = java.nio.file.Files.walk(java.nio.file.Path.of("src"))) {
+            java.util.List<String> violations = paths
+                    .filter(path -> path.toString().endsWith(".java"))
+                    .filter(path -> !path.normalize().endsWith(self))
+                    .map(path -> {
+                        try {
+                            String text = java.nio.file.Files.readString(path);
+                            boolean legacy = text.contains("com.label.module.")
+                                    || text.contains("com.label.common.aop")
+                                    || text.contains("com.label.common.config");
+                            return legacy ? path.toString() : null;
+                        } catch (Exception e) {
+                            throw new RuntimeException(e);
+                        }
+                    })
+                    .filter(java.util.Objects::nonNull)
+                    .toList();
+
+            org.assertj.core.api.Assertions.assertThat(violations).isEmpty();
+        }
+    }
+
     private static void assertClassExists(String fqcn) {
         assertThatCode(() -> Class.forName(fqcn)).doesNotThrowAnyException();
     }