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_deepseek_reasoning.py

@@ -24,7 +24,6 @@ from tradingagents.llm_clients.openai_client import (
     _input_to_messages,
 )
 
-
 # ---------------------------------------------------------------------------
 # _input_to_messages — the helper that handles list / ChatPromptValue / other
 # (Gemini bot review note: non-list inputs must also work)