android: add German translation

[thisisAcidic]

Adds German translation (values-de) covering all current strings.

Style choices:

• "du" form throughout
• Mirrors Apple iOS German terminology where applicable (Hörmodus, Geräuschunterdrückung, Transparenzmodus, Sprecherkennung, Bedienungshilfen, Reduzierung lauter Töne, Gesprächsverstärker, Hörhilfe, etc.)
• Brand names kept untranslated (AirPods, Bluetooth, Dynamic Island, Linux, Android, BLE, IRK, ENC_KEY, EQ, Xposed, OxygenOS, ColorOS)
• A few technical strings (e.g. Hook Offset, BLE-Advertisements) kept English where translating would obscure meaning

Tested on Oppo Find X9 Pro with system language set to German.