feat(run-ops): webapp db topology, flags, migration helpers + store/engine wiring

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: d-cs

apps/webapp/CLAUDE.md

@@ -75,8 +75,8 @@ const signal = getRequestAbortSignal();
 Access via `env` export from `app/env.server.ts`. **Never use `process.env` directly.**
 
 For testable code, **never import env.server.ts** in test files. Pass configuration as options instead:
-- `realtimeClient.server.ts` (testable service, takes config as constructor arg)
-- `realtimeClientGlobal.server.ts` (creates singleton with env config)
+- `realtime/nativeRealtimeClient.server.ts` (testable service, takes config as constructor arg)
+- `realtime/nativeRealtimeClientInstance.server.ts` (creates singleton with env config)
 
 ## Run Engine 2.0