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/schemas.py

@@ -0,0 +1,71 @@
+from typing import Literal
+from pydantic import BaseModel, Field
+
+
+class EndpointCapabilities(BaseModel):
+    id: str
+    kind: str
+    direction: Literal["input", "output"]
+    sample_rate: int = 16000
+    channels: int = 1
+    latency_class: Literal["low", "medium", "high"] = "medium"
+    supports_aec: bool = False
+    supports_barge_in: bool = False
+    networked: bool = False
+    bluetooth: bool = False
+    mobile: bool = False
+    default: bool = False
+
+
+class AudioChunk(BaseModel):
+    data: bytes
+    sample_rate: int = 16000
+    channels: int = 1
+    format: str = "wav"
+    timestamp_ms: int = 0
+
+
+class PipelineTrace(BaseModel):
+    raw_transcript: str | None = None
+    cleaned_transcript: str | None = None
+    semantic_response: str | None = None
+    spoken_response: str | None = None
+    tts_ready_text: str | None = None
+
+
+class SpeakRequest(BaseModel):
+    text: str = Field(min_length=1)
+    voice: str | None = None
+    language: str | None = None
+    output_endpoint: str | None = None
+    tts_provider: str | None = None
+
+
+class ChatRequest(BaseModel):
+    text: str = Field(min_length=1)
+    input_endpoint: str | None = None
+    output_endpoint: str | None = None
+    language: str | None = None
+    voice: str | None = None
+    stt_provider: str | None = None
+    llm_provider: str | None = None
+    tts_provider: str | None = None
+
+
+class SessionRouteRequest(BaseModel):
+    input_endpoint: str | None = None
+    output_endpoint: str | None = None
+    stt_provider: str | None = None
+    llm_provider: str | None = None
+    tts_provider: str | None = None
+    language: str | None = None
+
+
+class RouteInfo(BaseModel):
+    input_endpoint: str
+    output_endpoint: str
+    stt_provider: str
+    llm_provider: str
+    tts_provider: str
+    language: str
+