refactor: reorganize backend module boundaries

app/agent/skills/registry.py

@@ -10,10 +10,10 @@ from typing import Dict, List, Optional, Tuple
 from urllib.parse import urlencode, urljoin, urlparse
 
 from app.agent.skills.metadata import parse_skill_metadata
-from app.platform.cache import cached, fresh
-from app.platform.config import settings
-from app.platform.log import logger
-from app.foundation.http import RequestUtils
+from app.runtime.cache import cached, fresh
+from app.runtime.config import settings
+from app.runtime.log import logger
+from app.adapters.network.http import RequestUtils
 from app.foundation.singleton import WeakSingleton
 from app.foundation.url import UrlUtils