Add idiomatic documentation to Go, Java, Python, and Rust clients

clients/python/src/mxgateway/galaxy.py

@@ -34,6 +34,7 @@ class GalaxyRepositoryClient:
         stub: Any,
         channel: grpc.aio.Channel | None = None,
     ) -> None:
+        """Initialize the client with resolved options and a gRPC stub."""
         self.options = options
         self.raw_stub = stub
         self._channel = channel
@@ -72,9 +73,11 @@ class GalaxyRepositoryClient:
         )
 
     async def __aenter__(self) -> "GalaxyRepositoryClient":
+        """Return self to support ``async with`` usage."""
         return self
 
     async def __aexit__(self, *_exc_info: object) -> None:
+        """Close the client when leaving an ``async with`` block."""
         await self.close()
 
     async def close(self) -> None: