feat: add proxy middleware with circuit breaker fallback

Smart proxy to Bose servers with automatic fallback to local handlers.
Controlled via SOUNDCORK_MODE env var (default: local).

- ProxyMiddleware intercepts /marge, /bmx, /updates prefixes
- Circuit breaker per upstream server (opens on errors/404/5xx)
- 5-minute cooldown before retrying failed upstreams
- Traffic logging to JSONL file
- Adds httpx dependency

Addresses #152

Author: timvw

requirements.txt

@@ -2,6 +2,7 @@ black==25.9.0
 fastapi[standard]==0.120.1
 fastapi-etag==0.4.0
 gunicorn==23.0.0
+httpx==0.28.1
 pydantic-settings==2.11.0
 telnetlib3==2.0.8
 upnpclient==1.0.3

soundcork/config.py

@@ -20,6 +20,8 @@ class Settings(BaseSettings):
 
     base_url: str = ""
     data_dir: str = ""
+    soundcork_mode: str = "local"
+    soundcork_log_dir: str = "./logs/traffic"
     model_config = SettingsConfigDict(
         # `.env.private` takes priority over `.env.shared`
         env_file=(".env.shared", ".env.private")

soundcork/main.py

@@ -88,6 +88,10 @@ async def lifespan(app: FastAPI):
     lifespan=lifespan,
 )
 
+from soundcork.proxy import ProxyMiddleware
+
+app.add_middleware(ProxyMiddleware)
+
 
 # @lru_cache
 # def get_settings():