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.

refactored/managed-container.d/lifecycles/systemd.sh

@@ -0,0 +1,23 @@
+# Lifecycle adapter API 1. Quadlet remains the owner of container construction,
+# init/maintenance command, signal settings and service restart/exit policies.
+MC_LIFECYCLE_API=1
+
+mc_lifecycle_start()
+{
+    as_service_user systemctl --user start "$1"
+}
+
+mc_lifecycle_stop()
+{
+    as_service_user systemctl --user stop "$1"
+}
+
+mc_lifecycle_running()
+{
+    as_service_user systemctl --user is-active --quiet "$1"
+}
+
+mc_lifecycle_cat()
+{
+    as_service_user systemctl --user cat "$1"
+}