lint: ruff clean services/ (autofix + manual + ignore E741)

- 24 autofix safe (SIM105 contextlib.suppress, F401 unused imports,
  I001 import order, B007 unused loop var, F811 redef, F841 unused).
- 15 unsafe-fix (UP038 X|Y in isinstance, SIM108 ternary, ecc.).
- Manual fix: SIM102 nested if in deribit term_structure, E402 imports
  in test_cot.py + sentiment server.py.
- Ignore E741 (variabili 'l' in list comprehensions deribit/client.py
  — stilistico, non bug).

Tests: 478/478 verdi.

services/mcp-macro/tests/test_fetchers.py

@@ -366,6 +366,7 @@ async def test_fetch_cot_disagg_unknown_symbol():
 async def test_fetch_cot_extreme_positioning_flags_outliers(monkeypatch):
     """Mock fetch_cot_tff e fetch_cot_disagg per simulare history e ultimo punto."""
     from unittest.mock import AsyncMock
+
     from mcp_macro import fetchers as f
 
     # Simula una serie ES dove ultimo lev_funds_net è in basso (extreme_short)