feat(sync-ui): defer app quit until async cleanup resolves

- check-host participates in active-run coordination and can be cancelled
- shutdown() cancels and awaits the active launcher run on quit
- onWillQuit calls preventDefault and re-triggers quit once cleanup settles
- Snapshot mode awaits tracker quiescent before writing output
- Auto-scheduler catches synchronous triggerHostSync failures
- SCP endpoint accepts Windows absolute paths; cmd.exe rejects % in quoted values
- runAppCommand unified (inherit vs pipe stdio) in launcher/mpv.ts
- Docs: add --check, --json, --ui, --sync-cli, --make-temp/--remove-temp examples

src/core/services/stats-sync/shared.ts

@@ -8,8 +8,8 @@ import { selectOne, type OpenSyncDb, type SyncDb } from './driver';
 
 export { SCHEMA_VERSION };
 
-export type { SyncMergeSummary } from '../../../shared/sync/sync-events';
 import type { SyncMergeSummary } from '../../../shared/sync/sync-events';
+export type { SyncMergeSummary };
 
 export function createEmptyMergeSummary(): SyncMergeSummary {
   return {