Initial commit: Voice Assistant Gateway mit Konfig-/Routing-Fundament

- FastAPI-Gateway mit REST-Endpunkten (chat/speak/transcribe/devices/sessions/config)
- Geschichtete Konfiguration mit Profilen (local-dev/hybrid/cloud) via TOML + ENV
- Registry-Pattern + einheitliche Route-Aufloesung (Default->Profil->ENV->Session->Request)
- Device Router (strikt, Singleton) und Output-Lifecycle im Orchestrator
- OpenRouter-Adapter (STT multipart/LLM/TTS) + lokale Provider-Stubs
- Regelbasierte Pipeline (Cleaner/Spoken-Adapter/TTS-Normalizer)
- 22 automatisierte Tests; Doku: README, BEDIENUNGSANLEITUNG, Architektur
- Secrets ausschliesslich ueber Umgebung; .env und lokale config gitignored

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

deploy/voice-assistant.env.example

@@ -0,0 +1,3 @@
+HOST=0.0.0.0
+PORT=8080
+OPENROUTER_API_KEY=

deploy/voice-assistant.service

@@ -0,0 +1,15 @@
+[Unit]
+Description=Voice Assistant Gateway
+After=network.target
+
+[Service]
+Type=simple
+User=voice
+WorkingDirectory=/opt/voice-assistant
+EnvironmentFile=/etc/voice-assistant/voice-assistant.env
+ExecStart=/opt/voice-assistant/.venv/bin/uvicorn app.main:app --host ${HOST} --port ${PORT}
+Restart=always
+RestartSec=2
+
+[Install]
+WantedBy=multi-user.target