## Summary
Fixed PR comment labels showing raw translation keys instead of translated text.
**Problem:** The `CommentWidgetLine.tsx` and `ReviewCommentRenderer.tsx` components were using translation keys that didn't exist in the translation files:
- `comments.addReviewComment`
- `comments.addPlaceholder`
- `comments.editPlaceholder`
- `actions.cancel`
- `actions.saveChanges`
- `actions.copied`
**Solution:** Added the missing translation keys to `common.json` in all 6 locales:
- English (en)
- Spanish (es)
- Japanese (ja)
- Korean (ko)
- Simplified Chinese (zh-Hans)
- Traditional Chinese (zh-Hant)
**Verification:**
- ✅ `pnpm run check` passes (TypeScript and Rust checks)
- ✅ i18n check script confirms translation keys are consistent across all locales
- ✅ No duplicate JSON keys
e73c1b4bff