feat: runtime manager

notification/PLAN.md

@@ -363,3 +363,13 @@ The implementation is complete only when all of the following hold:
   notification types
 - admin notifications remain `email`-only
 - auth-code email still bypasses `Notification Service`
+
+## Note: Runtime Manager Catalog Extension
+
+The three administrator-only `runtime.*` notification types
+(`runtime.image_pull_failed`, `runtime.container_start_failed`,
+`runtime.start_config_invalid`) are added by the Runtime Manager
+implementation plan, not by this document. See
+[`../rtmanager/PLAN.md`](../rtmanager/PLAN.md) §«Stage 07. Notification
+intent constructors and catalog extension». No new stages are added here
+for that catalog growth.