fix: multiple bug fixes

isolated users, db backup, weird disconnect issues for long voice sessions,

toju-app/src/app/infrastructure/persistence/database.service.ts

@@ -85,6 +85,9 @@ export class DatabaseService {
   /** Retrieve the current (logged-in) user. */
   getCurrentUser() { return this.backend.getCurrentUser(); }
 
+  /** Retrieve the persisted current user ID without loading the full user. */
+  getCurrentUserId() { return this.backend.getCurrentUserId(); }
+
   /** Store the current user ID. */
   setCurrentUserId(userId: string) { return this.backend.setCurrentUserId(userId); }