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>

tests/unit/exchanges/alpaca/test_leverage_cap.py

@@ -1,8 +1,8 @@
 from __future__ import annotations
 
 import pytest
-from fastapi import HTTPException
 from cerbero_mcp.exchanges.alpaca.leverage_cap import enforce_leverage, get_max_leverage
+from fastapi import HTTPException
 
 
 def test_get_max_leverage_returns_creds_value():

tests/unit/exchanges/bybit/test_leverage_cap.py

@@ -1,8 +1,8 @@
 from __future__ import annotations
 
 import pytest
-from fastapi import HTTPException
 from cerbero_mcp.exchanges.bybit.leverage_cap import enforce_leverage, get_max_leverage
+from fastapi import HTTPException
 
 
 def test_get_max_leverage_returns_creds_value():

tests/unit/exchanges/deribit/test_leverage_cap.py

@@ -1,8 +1,8 @@
 from __future__ import annotations
 
 import pytest
-from fastapi import HTTPException
 from cerbero_mcp.exchanges.deribit.leverage_cap import enforce_leverage, get_max_leverage
+from fastapi import HTTPException
 
 
 def test_get_max_leverage_returns_creds_value():

tests/unit/exchanges/hyperliquid/test_leverage_cap.py

@@ -1,8 +1,8 @@
 from __future__ import annotations
 
 import pytest
-from fastapi import HTTPException
 from cerbero_mcp.exchanges.hyperliquid.leverage_cap import enforce_leverage, get_max_leverage
+from fastapi import HTTPException
 
 
 def test_get_max_leverage_returns_creds_value():