vibey-testinglisted

# vibey testing ## Coverage floors — not targets Every layer carries a **100% branch coverage floor**, enforced in CI as four separate gates: ```bash uv run pytest -q -p no:cacheprovider --cov=vibey.domain --cov-branch --cov-fail-under=100 uv run pytest -q -p no:cacheprovider --cov=vibey.application --cov-branch --cov-fail-under=100 uv run pytest -q -p no:cacheprovider --cov=vibey.infrastructure --cov-branch --cov-fail-under=100 uv run pytest -q -p no:cacheprovider --cov=vibey.cli --cov-branch --cov-fail-under=100 ``` The build **fails** if any layer drops below 100%. This is not aspirational. ## Postgres integration tests — never mocked All `tests/infrastructure/db/` tests run against a **real ephemeral Postgres** via the `migrated_pool` and `project_id` fixtures in `tests/infrastructure/db/conftest.py`. Every test drops and recreates the `public` schema before running. **Why real Postgres, never mocked:** because `SELECT ... FOR UPDATE SKIP LOCKED` semantics are the thing under test. A mock cannot faithfully represent concurrent worker contention, lease expiry, or the reaper reclaiming expired leases. See ADR-0002. Set `VIBEY_TEST_DATABASE_URL` before running: ```bash export VIBEY_TEST_DATABASE_URL="postgresql://$(whoami)@localhost:5432/vibey_test" ``` CI uses a Postgres 17 service container. ## Property tests — the safety-critical invariants **Rotation fairness** (`tests/domain/test_rotation.py`): - Over any eligible set and any weight vector, every engine is s