feat(db): implement PostgreSQL monitoring and maintenance features

Added PostgreSQL monitoring and maintenance capabilities to the API, including new endpoints for instance-level metrics, maintenance operations, and job scheduling. Updated the HTTP API to support PostgreSQL monitoring routes and integrated a background scheduler for metrics collection. Enhanced the CLI with database commands for maintenance tasks. Updated documentation to reflect these changes.

internal/httpapi/routes.go

@@ -76,6 +76,8 @@ func (s *Server) registerV1(m *http.ServeMux) {
 	m.HandleFunc("GET /speakers/{speaker_id}/bundle/{revision_id}", s.handleNodeBundle)
 	m.HandleFunc("POST /nodes/enroll", s.handleNodeEnroll)
 	s.registerCRUDRoutes(m)
+	s.registerPostgresMonitoringRoutes(m)
+	s.registerPostgresMaintenanceRoutes(m)
 }
 
 func (s *Server) handleHealth(w http.ResponseWriter, r *http.Request) {