feat: initial voice assistant implementation

5-state machine (LAUSCH/AUFNAHME/GENERATOR/VORLESE/DIALOG) with:
- Wake-word detection via openwakeword (hey_jarvis)
- Speech-to-text via faster-whisper large-v3 (GPU)
- LLM streaming via OpenAI-compatible backends (llama.cpp/ollama/openai)
- TTS via piper with automatic language detection and voice selection
- Selectable mic input (ReSpeaker, MOTU M2, camera, bluetooth, index)
- Selectable audio output sink
- Control words during playback (Stopp/Pause/Weiter/Noch einmal/…)
- "Stopp" abort in all active states → LAUSCH

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.gitignore

@@ -0,0 +1,40 @@
+# Python
+__pycache__/
+*.py[cod]
+*.pyo
+*.pyd
+.Python
+*.egg-info/
+dist/
+build/
+*.egg
+.eggs/
+
+# Virtuelle Umgebungen
+.venv/
+venv/
+env/
+.env
+
+# IDE / Editor
+.idea/
+.vscode/
+*.swp
+*.swo
+*~
+
+# Claude Code
+.claude/
+
+# Piper TTS — Sprachmodelle (groß, nicht versionieren)
+*.onnx
+*.onnx.json
+
+# Audio-Testdateien
+*.wav
+*.mp3
+*.flac
+*.ogg
+
+# Logs
+*.log