chore(V2): cleanup quality gate

- ruff: contextlib.suppress al posto di try/except/pass (client_registry, test_env_routing)
- rimozione services/ legacy (residuo da git rm)
- fix integration test fixture: rimosso sys.modules.pop che inquinava module references nei test successivi (test_audit, test_client_init_default_http)

254 test passano. Ruff: clean. Mypy: 68 warning preesistenti dal codice V1 migrato (strict=false).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/cerbero_mcp/client_registry.py

@@ -2,6 +2,7 @@
 from __future__ import annotations
 
 import asyncio
+import contextlib
 from collections import defaultdict
 from collections.abc import Awaitable, Callable
 from typing import Any, Literal
@@ -34,8 +35,6 @@ class ClientRegistry:
             close = getattr(client, "aclose", None)
             if close is None:
                 continue
-            try:
+            with contextlib.suppress(Exception):
                 await close()
-            except Exception:
-                pass
         self._clients.clear()