fix: prevent unhandled promise rejection from restoration transaction cleanup

Add catch handler to restoration transaction's isPersisted promise to prevent
unhandled rejection when rollback() is called during cleanup. The rollback
calls reject(undefined) which would otherwise cause an unhandled rejection error.

Author: claude

packages/offline-transactions/src/executor/TransactionExecutor.ts

@@ -269,6 +269,13 @@ export class TransactionExecutor {
           mutationFn: async () => {},
         })
 
+        // Prevent unhandled promise rejection when cleanup calls rollback()
+        // We don't care about this promise - it's just for holding mutations
+        restorationTx.isPersisted.promise.catch(() => {
+          // Intentionally ignored - restoration transactions are cleaned up
+          // via cleanupRestorationTransaction, not through normal commit flow
+        })
+
         restorationTx.applyMutations(offlineTx.mutations)
 
         // Register with each affected collection's state manager