feat: Add German language localization

[ro011110ot]

This Pull Request adds full German localization support to the manager app. It introduces the German translation strings, updates the existing language resource files, and registers the new locale within the application's configuration.
Changes

Added German translations file: /app/src/main/res/values-de/strings.xml

Updated default strings configuration (/app/src/main/res/values/strings.xml):

    Added <string name="language_german">German</string>

Updated Chinese translation file (/app/src/main/res/values-zh/strings.xml):

    Added <string name="language_german">德语</string>

Updated language routing logic (/app/src/main/java/com/noobexon/xposedfakelocation/manager/localization/LanguageOption.kt):

    Added private const val GERMAN_LANGUAGE_TAG = "de-DE"

    Added GERMAN(GERMAN_LANGUAGE_TAG, R.string.language_german) entry to the LanguageOption enum class.

How it was tested

Device Model: Xiaomi Redmi Note 12 Pro 4G (sweet_k6a / sweet2)

Android Version: Android 16.0 (LineageOS 23.2)

Verification: Verified that the German language is correctly detected and automatically applied when the Android system language is set to German. The strings render properly in the UI.

Known Limitations / Follow-up Work

None. The translation is complete and matches the current core resource structure.

[noobexon1]

Hi @ro011110ot, Thanks for taking the time to contribute to XposedFakeLocation! ❤️

I had quite a busy week, but I'll try to review both of your PRs during the weekend. If all is well, I'll be happy to merge them 🙂