feat(db,contracts): trash_item migration and file manager contract refinements

- 0024_trash: trash_item table + unique idempotency index on artifact(files_idem)
- files.ts: TrashItemRow, delete planId/planExpiresAt, organize group warnings,
  scrape returns refreshMetadata taskId
- registry tests list the new table/row schema

Co-Authored-By: Claude Opus 5.5 <[email protected]>

packages/contracts/test/db-sync.test.ts

@@ -93,6 +93,8 @@ const ROWS: Record<string, { row: Obj; dbOnly?: string[]; apiOnly?: string[] }>
   BrowserSession: { row: C.BrowserSession },
   BrowserTab: { row: C.BrowserTab },
   BrowserControlLease: { row: C.BrowserControlLease },
+  // W5-A 文件管理回收站(0024)
+  TrashItem: { row: C.TrashItemRow },
 };
 
 /** 引擎自有表(@umt/tasks 内部使用,不经 API 暴露),不要求 Row schema */