Freeze lab-tested PostgreSQL plugin engine

Extract PostgreSQL, Podman runtime and systemd lifecycle adapters while preserving existing lifecycle and scoring behavior. Update RPM layout and add guarded operator-run lab harnesses.

Record successful manual stop/start, promotion, demotion and rewind-only rejoin with pinned installed hashes. The unfenced lab does not validate automatic failover, Pacemaker-managed transitions or divergent-data rewind.

Validation: 103 offline tests, original-function differential checks, checksum manifest and whitespace checks passed.

tests/verify_promotion_state_cli.py

@@ -12,7 +12,7 @@ from test_disconnected_state import CONNECTED, DISCONNECTED
 assert os.geteuid() == 0 and os.environ.get('MC_DISPOSABLE_STATE_TEST') == '1', (
     'Run only in a disposable container with MC_DISPOSABLE_STATE_TEST=1')
 helper = (Path(sys.argv[1]) if len(sys.argv) > 1 else
-          Path(__file__).resolve().parents[1] / 'refactored/managed-container.d/promotion_state.py')
+          Path(__file__).resolve().parents[1] / 'refactored/managed-container.d/applications/postgresql/promotion_state.py')
 resource = 'mc-disposable-' + uuid.uuid4().hex
 args = ['python3', str(helper), resource, 'test-owner', 'test.service', 'test-container', '300']