1. get_task_executor mocking: same dependency_overrides fix as the previous
commit, applied to this file's remaining patch('src.main.get_task_executor')
call sites (test_valid_api_key_allows_access, test_create_task_with_valid_data,
test_trigger_task_endpoint, test_stats_endpoint_returns_metrics,
test_executions_endpoint_returns_history, test_executions_filter_by_task_name).
2. test_create_task_missing_fields_returns_400 asserted a status this endpoint
cannot return. `task: TaskCreate` in src/main.py is a plain Pydantic request
body with no custom validation for missing fields — FastAPI's own
dependency-resolution layer rejects the request before create_task's body
runs, and that layer always answers 422, not 400. There is no code path in
this repo, at any point in its git history, that produces 400 for this
request. Renamed to test_create_task_missing_fields_returns_422 and the
assertion updated to match; source unchanged.
Kept together in one commit because both live in the same small file and were
found in the same pass, rather than risk a manual hunk split on tightly
interleaved diff context.