Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@frontend/src/hooks/useExport.ts`:
- Around line 124-126: The onProgress callback is being called directly at
multiple locations throughout the useExport hook without exception handling, and
the cleanup operations (setIsSelecting(false) and isSelectingRef.current =
false) are not guaranteed to execute if onProgress throws an exception. Wrap all
direct calls to onProgress in try/catch blocks to isolate any callback
exceptions, and ensure that the cleanup logic for setIsSelecting and
isSelectingRef.current is moved into a finally block so it executes regardless
of whether the onProgress callback succeeds or fails. This applies to the
onProgress calls at the initial progress notification, the intermediate progress
updates, and the final completion notification to prevent operation locks from
remaining active when the callback fails.

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@frontend/src/hooks/useExport.ts`:
- Line 204: 進捗更新が失敗時のcontinue経路で抜け落ちています。useExport.ts の import ループ内で
safeOnProgress を呼んでいる箇所を見直し、Line 154 / Line 180 の失敗分岐でも必ず実行されるように、同じループの
try/finally の finally 側へ移動してください。これにより importedImages.length
を基準にした進捗表示が各画像処理後に必ず更新されます。