feat: Porcupine Wake-Word Integration (Built-In Keywords, "Jarvis" default)

WakeWordService wrappt jetzt Picovoice Porcupine:
  - loadFromStorage(): Access Key + Keyword aus AsyncStorage, init Porcupine
  - configure(key, keyword): Settings-Wechsel, Re-Init
  - start(): wenn Porcupine bereit → 'armed' (passives Lauschen),
    sonst Fallback auf direktes 'conversing' (klassischer Modus)
  - onWakeDetected: Porcupine pausieren → 'conversing' → wakeCallback
  - endConversation: Porcupine wieder starten → 'armed' (Wake-Word weiter
    aktiv im Hintergrund, kein erneuter Tap noetig)
  - Pro Geraet eigene Wahl: jeder User kann sein eigenes Wake-Word haben

Settings: neuer Bereich "Wake-Word"
  - Picovoice Access Key Input (mit Eye-Toggle), kostenlos auf
    console.picovoice.ai
  - Built-In Keyword Chips: jarvis, computer, picovoice, porcupine,
    bumblebee, terminator, alexa, hey google, ok google, hey siri
  - "Speichern + Aktivieren" Button mit Status-Feedback
  - Hinweis dass "ARIA" Custom-Keyword spaeter via Diagnostic kommt

ChatScreen: ruft wakeWordService.loadFromStorage() beim Mount.

package.json: @picovoice/porcupine-react-native + react-native-voice-processor
hinzugefuegt — npm install + native rebuild noetig.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

android/package.json

@@ -24,7 +24,9 @@
     "react-native-camera-kit": "^13.0.0",
     "@react-native-async-storage/async-storage": "^1.21.0",
     "react-native-fs": "^2.20.0",
-    "react-native-audio-recorder-player": "^3.6.7"
+    "react-native-audio-recorder-player": "^3.6.7",
+    "@picovoice/porcupine-react-native": "^3.0.6",
+    "@picovoice/react-native-voice-processor": "^1.2.3"
   },
   "devDependencies": {
     "typescript": "^5.3.3",