fix(client/python): reachable cert-validation flag; bounded off-loop TOFU probe; license/marker fixes (Client.Python-027..031)

clients/python/src/zb_mom_ww_mxgateway/galaxy.py

@@ -52,6 +52,7 @@ class GalaxyRepositoryClient:
         api_key: str | None = None,
         plaintext: bool = False,
         ca_file: str | None = None,
+        require_certificate_validation: bool = False,
         server_name_override: str | None = None,
         stub: Any | None = None,
     ) -> "GalaxyRepositoryClient":
@@ -62,13 +63,16 @@ class GalaxyRepositoryClient:
             api_key=api_key,
             plaintext=plaintext,
             ca_file=ca_file,
+            require_certificate_validation=require_certificate_validation,
             server_name_override=server_name_override,
         )
 
         if stub is not None:
             return cls(options=resolved, stub=stub)
 
-        channel = create_channel(resolved)
+        # create_channel may perform a blocking TLS certificate probe (TOFU
+        # default); run it off the event loop so connect never freezes the loop.
+        channel = await asyncio.to_thread(create_channel, resolved)
         return cls(
             options=resolved,
             stub=galaxy_pb_grpc.GalaxyRepositoryStub(channel),