feat: add Traditional Chinese localization

[yysu]

Summary

• Add zh-Hant.lproj/Localizable.strings with 117 translated strings, matching the coverage of the existing zh-Hans localization introduced in feat: add Chinese (Simplified) localization #8
• Register zh-Hant in project.pbxproj (PBXFileReference, PBXVariantGroup, knownRegions)
• Uses terminology throughout (e.g. 磁碟/存取/檔案/垃圾桶/應用程式/排程/快取/記錄檔) rather than the mainland terms used by zh-Hans

Notes

• No source code changes — PR feat: add Chinese (Simplified) localization #8 already did the LocalizedStringKey / String(localized:) wiring, so adding a new .lproj bundle is sufficient
• Verified locally by running xcodebuild and confirming zh-Hant.lproj ships inside PureMac.app/Contents/Resources/

Test plan

• Change system language to 繁體中文 (Traditional Chinese) in System Settings → Language & Region
• Launch PureMac and verify all UI text displays in Traditional Chinese
• Run a scan and confirm scan/clean button labels are localized
• Check Settings (Schedule / General / About tabs) for correct translations
• Verify Simplified Chinese and English are unaffected when system language is set accordingly

[jay900604]

沒想到也有人為此專案提供了正體中文語言翻譯貢獻，我晚了一步，我翻譯好了還沒進行上傳而已，哈哈！

[momenbasel]

Merged manually after rebasing onto main (conflict in project.pbxproj from PRs #13 and #20). All 116 zh-Hant strings and pbxproj registrations are in main now. Thanks @yysu!

[momenbasel]

Thanks @yysu for the thorough localization work! 116 strings with proper Traditional Chinese terminology throughout - really solid contribution. Appreciate you verifying the build locally too.

[yysu]

Thank you @momenbasel for the amazing app.