fix: move service_signatures.json inside app package and bump to 1.3.3

The file was in /app/data/ which gets overwritten by the Docker volume
mount (backend_data:/app/data), making it invisible at runtime and
causing scan failures on fresh installs. Moved to /app/app/data/ so
it stays baked into the image.

backend/app/main.py

@@ -22,7 +22,7 @@ async def lifespan(app: FastAPI) -> AsyncGenerator[None, None]:
 
 app = FastAPI(
     title="Homelable API",
-    version="1.3.2",
+    version="1.3.3",
     lifespan=lifespan,
 )