feat(app): Wake-Word komplett on-device via openWakeWord (ONNX)

Picovoice/Porcupine raus — neuer Stack ist openWakeWord (Apache 2.0,
on-device, ONNX Runtime). Kein API-Key, keine Lizenzgebuehren, Audio
verlaesst das Geraet nicht. Eigene Wake-Words sind via openWakeWord-
Notebook gratis trainierbar.

Pipeline (alles im OpenWakeWordModule.kt):
  1. AudioRecord 16kHz mono int16 in 1280-Sample-Chunks (80ms)
  2. melspectrogram.onnx → 32-mel Frames (mel/10 + 2 wie in Python)
  3. embedding_model.onnx, 76-Frame Sliding Window (stride 8) → 96-dim
  4. hey_jarvis.onnx (oder anderes Keyword) auf letzten 16 Embeddings
  5. Sigmoid-Score, threshold/patience/debounce-Filter
  6. RN-Event "WakeWordDetected" raus

Mitgelieferte Modelle in assets/openwakeword/: hey_jarvis (Default),
alexa, hey_mycroft, hey_rhasspy. Externe Service-API (start/stop/
configure/onWakeWord/...) bleibt identisch — ChatScreen unveraendert.

build.gradle: com.microsoft.onnxruntime:onnxruntime-android:1.17.1
package.json: @picovoice/porcupine-react-native + voice-processor raus
SettingsScreen: AccessKey-Feld weg, neue Keyword-Liste mit Labels
README: Wake-Word-Sektion komplett umgeschrieben (kein Picovoice mehr)

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

android/package.json

@@ -24,9 +24,7 @@
     "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",
-    "@picovoice/porcupine-react-native": "3.0.5",
-    "@picovoice/react-native-voice-processor": "1.2.3"
+    "react-native-audio-recorder-player": "^3.6.7"
   },
   "devDependencies": {
     "typescript": "^5.3.3",