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/exchanges/bybit/client.py

@@ -3,9 +3,10 @@ from __future__ import annotations
 import asyncio
 from typing import Any
 
+from pybit.unified_trading import HTTP
+
 from cerbero_mcp.common import indicators as ind
 from cerbero_mcp.common import microstructure as micro
-from pybit.unified_trading import HTTP
 
 
 def _f(v: Any) -> float | None: