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_ollama_base_url.py

@@ -18,8 +18,8 @@ def _resync_reloaded_modules():
     doesn't leak across test modules.
     """
     yield
-    import cli.utils
     import cli.main
+    import cli.utils
     importlib.reload(cli.utils)
     importlib.reload(cli.main)