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>

tests/test_routing.py

@@ -0,0 +1,46 @@
+import pytest
+
+from app.config import Settings
+from app.errors import UnknownComponentError
+from app.dependencies import (
+    resolve_route,
+    get_llm_provider,
+    get_tts_provider,
+    session_manager,
+)
+
+
+def test_default_route_from_settings():
+    cfg = Settings()
+    route = resolve_route(cfg=cfg)
+    assert route.stt_provider == cfg.default_stt_provider
+    assert route.llm_provider == cfg.default_llm_provider
+    assert route.input_endpoint == cfg.default_input_endpoint
+    assert route.language == cfg.default_language
+
+
+def test_request_overrides_win():
+    route = resolve_route(overrides={"llm_provider": "openrouter", "output_endpoint": "loopback"})
+    assert route.llm_provider == "openrouter"
+    assert route.output_endpoint == "loopback"
+
+
+def test_session_then_request_precedence():
+    session_manager.update("s_test", {"tts_provider": "piper", "language": "en"})
+    route = resolve_route("s_test")
+    assert route.tts_provider == "piper"
+    assert route.language == "en"
+
+    # Request schlaegt Session.
+    route2 = resolve_route("s_test", {"tts_provider": "chatterbox"})
+    assert route2.tts_provider == "chatterbox"
+    assert route2.language == "en"
+
+
+def test_registry_unknown_provider_raises():
+    with pytest.raises(UnknownComponentError):
+        get_llm_provider("does-not-exist")
+
+
+def test_registry_known_provider():
+    assert type(get_tts_provider("piper")).__name__ == "PiperTTSProvider"