android: in-app language picker + Korean translation

[QuerTeal]

Summary

In-app language picker

• Adds a Language section to the app settings. It lists System default plus every locale in the generated locale config (generateLocaleConfig = true, read via LocaleConfig).
• Each language is shown by its own display name (e.g. 한국어, Deutsch).
• It uses LocaleManager.setApplicationLocales() (minSdk is 33), so the choice is the same per-app language setting found in the system settings.
• The section is placed outside the hasConnectedToAACP / premium block, so it is always reachable.
• Adds two new strings to values/: language and system_default.

Korean translation (values-ko)

• All 344 translatable strings are translated.
• AirPods feature names follow Apple's official Korean terminology from the Korean AirPods User Guide (support.apple.com/ko-kr/guide/airpods). A few notable ones where the "obvious" translation differs from Apple's:

English	Apple Korean
Conversational Awareness	대화 인지
Noise Cancellation	노이즈 캔슬링
Transparency	주변음 허용
Personalized Volume	개인 맞춤형 음량
Automatic Ear Detection	자동으로 착용 감지
Noise Cancellation with Single AirPod	AirPod 한 개 착용 시 노이즈 캔슬링
Conversation Boost	대화 부스트
Pause media when falling asleep	잠들면 미디어 일시 정지
Camera Remote	카메라 리모컨

• Product names are kept in Latin script (AirPods, AirPod, Bluetooth), as Apple does.
• Format arguments were checked against values/ and all of them match.

Not covered: about 100 UI strings are hardcoded in Kotlin (e.g. NoiseControlWidgetConfigurationActivity, HeartRateScreen, DebugScreen) and remain English. Moving them to resources could be a follow-up PR.

Testing

• assembleFossDebug builds.
• The generated _generated_res_locale_config.xml now includes ko.
• A script check confirmed that values-ko covers every translatable key in values/ with matching format arguments.
• Installed on a Galaxy S26 Ultra (system locale ko-KR, One UI 9.0). Per-app locale is unset (cmd locale get-app-locales → []), so System default resolves to values-ko.
• Verified on device: switching languages from the picker recreates the UI in the selected language.

🤖 Generated with Claude Code