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>

app/api/speak.py

@@ -0,0 +1,60 @@
+from io import BytesIO
+
+from fastapi import APIRouter, HTTPException, Query
+from fastapi.responses import StreamingResponse
+
+from app.config import settings
+from app.errors import RoutingError
+from app.dependencies import (
+    resolve_route,
+    build_orchestrator,
+    resolve_output_endpoint,
+)
+from app.schemas import SpeakRequest
+
+router = APIRouter()
+
+
+@router.post("/speak")
+async def speak(
+    payload: SpeakRequest,
+    session_id: str | None = Query(
+        default=None,
+        description="Optional session id to apply a stored route",
+    ),
+):
+    overrides = {
+        "output_endpoint": payload.output_endpoint,
+        "language": payload.language,
+        "tts_provider": payload.tts_provider,
+    }
+    route = resolve_route(session_id, overrides)
+    voice = payload.voice or settings.openrouter_tts_voice
+
+    try:
+        orchestrator = build_orchestrator(route)
+        output = await resolve_output_endpoint(route)
+    except RoutingError as exc:
+        raise HTTPException(status_code=422, detail=str(exc))
+
+    try:
+        audio = await orchestrator.speak_only(
+            payload.text,
+            voice=voice,
+            language=route.language,
+            output=output,
+        )
+
+        headers = {
+            "Content-Language": route.language,
+            "X-Audio-Format": "pcm",
+            "X-Audio-Sample-Rate": "24000",
+            "X-Audio-Channels": "1",
+            "X-Audio-Sample-Width": "16",
+            "X-Output-Endpoint": route.output_endpoint,
+            "X-TTS-Provider": route.tts_provider,
+        }
+        return StreamingResponse(BytesIO(audio), media_type="audio/pcm", headers=headers)
+
+    except Exception as exc:
+        raise HTTPException(status_code=502, detail=str(exc))