refactor(string): split utilities by responsibility

app/application/site/__init__.py

@@ -1,25 +1 @@
 """站点目录、认证与索引资源的应用能力包。"""
-
-from importlib.machinery import EXTENSION_SUFFIXES
-from pathlib import Path
-
-
-def _include_legacy_resource_directory(
-        package_paths: list[str], package_dir: Path
-) -> None:
-    """canonical 扩展缺失时允许读取旧 Docker 更新器写入的资源目录。"""
-    extension_names = tuple(f"sites{suffix}" for suffix in EXTENSION_SUFFIXES)
-    if any((package_dir / name).is_file() for name in extension_names):
-        return
-
-    legacy_dir = package_dir.parent.parent / "helper"
-    if (
-            legacy_dir.is_dir()
-            and any((legacy_dir / name).is_file() for name in extension_names)
-            and str(legacy_dir) not in package_paths
-    ):
-        # 旧镜像内固化的 mp_update.sh 无法随源码热更新，只在过渡场景扩展包搜索路径。
-        package_paths.append(str(legacy_dir))
-
-
-_include_legacy_resource_directory(__path__, Path(__file__).resolve().parent)