refactor(offline): co-locate offline feature into features/offline

src/features/offline/hooks/useZipDownloadBridge.ts

@@ -0,0 +1,14 @@
+import { useEffect } from 'react';
+import { listen } from '@tauri-apps/api/event';
+import { useZipDownloadStore } from '@/features/offline/store/zipDownloadStore';
+
+/** ZIP download progress events from Rust. */
+export function useZipDownloadBridge() {
+  useEffect(() => {
+    let unlisten: (() => void) | undefined;
+    listen<{ id: string; bytes: number; total: number | null }>('download:zip:progress', e => {
+      useZipDownloadStore.getState().updateProgress(e.payload.id, e.payload.bytes, e.payload.total);
+    }).then(u => { unlisten = u; });
+    return () => { unlisten?.(); };
+  }, []);
+}