feat(app): in-app asset picker (wechat_assets_picker) - unlimited multi-select with range selection

Review fixes: per-asset originFile error isolation (failed asset skipped, not whole batch); drop maxSdkVersion from READ_MEDIA_VISUAL_USER_SELECTED (API 34+, no upper bound); originFile doc accuracy (API 30+ direct path vs Android 10 ScopedCache copy).

Co-Authored-By: Claude Code <noreply@anthropic.com>

apps/mobile/lib/pages/capture_page.dart

@@ -304,7 +304,7 @@ class _CapturePageState extends ConsumerState<CapturePage>
 
   /// 相册多选入队（目标 = 当前相册与分类；入口=底部缩略图位）。
   Future<void> _pickFromGallery() async {
-    final paths = await ref.read(multiImagePickerProvider)();
+    final paths = await ref.read(multiImagePickerProvider)(context);
     if (paths.isEmpty || !mounted) return;
     final l10n = AppLocalizations.of(context);
     final messenger = ScaffoldMessenger.of(context);