GRC's SimpleXMLRPCServer uses register_instance() which doesn't expose system.listMethods. Wrap the connectivity check in a try/except so a Fault is treated as "connected" while ConnectionRefusedError still propagates.
Add RuntimeProvider with 17 MCP tools for controlling running flowgraphs: - Container lifecycle: launch, list, stop, remove - Connection: connect by URL or container name - Variable control: list, get, set via XML-RPC introspection - Flowgraph execution: start, stop, lock, unlock - Visual feedback: screenshot capture, container logs Docker is optional - 10 tools work without it for external flowgraphs. Includes: - DockerMiddleware wrapping docker.DockerClient - XmlRpcMiddleware wrapping xmlrpc.client.ServerProxy - Dockerfile with Xvfb + ImageMagick + VNC for headless QT - 29 new unit tests (71 total)
