test: add integration tests for CLI status command JSON output

[Samanyu-dev]

Summary

• Added a narrow regression test in tests/test_cli_status.py to cover the hermes-collab status --json CLI command.
• Verified that the command executes successfully and returns valid JSON with the expected top-level fields (overview, runs, lessons).
• Ensured the test is independent of real runtime databases and machine-specific values by utilizing an isolated temporary SQLite store.

Type of change

• Bug fix
• Feature
• Documentation/localization
• Security or safety hardening
• Release/process update

(Note: Adding test coverage doesn't perfectly fit a single category above, but you can leave them unchecked or check whatever fits your team's convention).

Verification

List the exact commands or checks run, and include failures if any:

apple@192 hermes-collab-engine % PYTHONPATH=src python3 -m unittest tests.test_cli_status -v
test_status_json_returns_expected_structure (tests.test_cli_status.StatusCliTests) ... ok

----------------------------------------------------------------------
Ran 1 test in 0.063s

OK

Linked issues
Closes #4