chore(lint): make the repository ruff-clean under the strict select

Clear the deferred full-repo lint backlog so the whole tree passes the strict
ruff select (E,W,F,I,B,UP,C4,SIM). Mechanical fixes dominate: import sorting,
pep585/604 annotations, dropped dead imports, and whitespace. The few semantic
changes are behavior-preserving: declare __all__ on the agent_utils and
alpha_vantage re-export hubs; expand 'from x import *' to explicit names; use
immutable tuple defaults instead of mutable list defaults; contextlib.suppress
for try/except/pass; and narrow an over-broad assertRaises.

tests/test_vendor_routing.py

@@ -6,7 +6,6 @@ Regressions for #988 (explicit single-vendor config still fell back to others),
 were swallowed without a trace).
 """
 import copy
-import logging
 import unittest
 from unittest import mock
 
@@ -76,9 +75,9 @@ class VendorRoutingTests(unittest.TestCase):
         # #989: primary errors + fallback no-data -> NO_DATA, but the failure
         # must be visible in logs (broken primary not hidden).
         set_config({"data_vendors": {"core_stock_apis": "yfinance,alpha_vantage"}})
-        with self._route({"yfinance": _raises(ValueError("boom")), "alpha_vantage": _no_data}):
-            with self.assertLogs("tradingagents.dataflows.interface", level="WARNING") as cm:
-                result = interface.route_to_vendor("get_stock_data", "AAPL", "2026-01-01", "2026-01-10")
+        with self._route({"yfinance": _raises(ValueError("boom")), "alpha_vantage": _no_data}), \
+                self.assertLogs("tradingagents.dataflows.interface", level="WARNING") as cm:
+            result = interface.route_to_vendor("get_stock_data", "AAPL", "2026-01-01", "2026-01-10")
         self.assertIn("NO_DATA_AVAILABLE", result)
         joined = "\n".join(cm.output)
         self.assertIn("boom", joined)            # the real error surfaced in logs