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_sql.py

@@ -18,7 +18,7 @@ ROOT = Path(__file__).resolve().parents[1]
 with tempfile.TemporaryDirectory(prefix='mc-score-sql-') as directory:
     query_file = Path(directory) / 'query.sql'
     env = dict(os.environ, QUERY_FILE=str(query_file))
-    extract = '. ' + shlex.quote(str(ROOT / 'refactored/managed-container.d/postgres.sh')) + '''
+    extract = '. ' + shlex.quote(str(ROOT / 'refactored/managed-container.d/runtimes/podman.sh')) + '\n. ' + shlex.quote(str(ROOT / 'refactored/managed-container.d/applications/postgresql/postgres.sh')) + '''
 as_service_user() { printf '%s' "${@: -1}" > "$QUERY_FILE"; echo t; }
 mc_pg_promotion_eligible
 '''