Add TDD tests that prove bug #797 exists: the read-only `agents actor list`
command triggers database writes via `ActorRegistry.list_actors()` calling
`ensure_built_in_actors()`, which invokes `upsert_actor()` and potentially
`set_default_actor()` on every invocation.
Behave scenarios (features/tdd_actor_list_no_db_update.feature):
- Assert upsert_actor is not called during actor list (fails: bug present)
- Assert set_default_actor is not called during actor list (fails: bug present)
Robot Framework tests (robot/tdd_actor_list_no_db_update.robot):
- Integration smoke tests via helper script with same assertions
- Both test cases fail as expected, inverted by tdd_expected_fail_listener
All tests tagged @tdd_expected_fail @tdd_bug @tdd_bug_797 per the mandatory
TDD bug-fix workflow. The inversion mechanism converts the expected failures
to passes in CI. When bug #797 is fixed, the @tdd_expected_fail tag will be
removed and the tests will run normally.
Quality gates: lint pass, typecheck pass, coverage 98.22% (>97%).
ISSUES CLOSED: #841
aditya