test(cron): cover session_search with cron session db

[iacker]

Summary

• add a regression test proving cron jobs pass their SQLite session DB through to session_search
• exercise the cron AIAgent(session_db=...) wiring through run_job
• avoid LLM summarization in the test by asserting the no-match search path

Testing

• source venv/bin/activate && python -m pytest tests/cron/test_scheduler.py::TestRunJobSessionPersistence -q -n 0
• source venv/bin/activate && python -m pytest tests/cron/test_scheduler.py::TestRunJobSessionPersistence::test_run_job_passes_session_db_and_cron_platform tests/cron/test_scheduler.py::TestRunJobSessionPersistence::test_cron_session_search_uses_passed_session_db -q -n 0

Notes

• During verification, the broader tests/cron/test_scheduler.py -q suite still shows pre-existing failures in TestSilentDelivery::* and TestTickAdvanceBeforeRun::test_advance_called_before_run_job on the current base branch. This PR does not touch that logic.

Closes #6563

[trevorgordon981]

✅ Tests added by this PR run successfully. The only failures observed are import‑related (run_agent.AIAgent) and not due to the test changes themselves. The new coverage for cron scheduler helpers is solid. Great work!

[iacker]

Superseded by #53327 — rebased onto current main. The original test patched tools.session_search_tool._summarize_session and model_tools._discover_tools (both removed since) and froze an exact arg set that has changed; #53327 drops the stale patches and asserts the wiring invariant instead. Closing in favor of #53327.