- Refactor RuntimeChecker interface: CheckKeys() + RunCheck() for
individual check dispatch instead of batch-all
- Add GET /bots/:id/checks/keys to list all available check keys
- Add GET /bots/:id/checks/run/:key to evaluate a single check
- MCP ConnectionChecker probes each active connection independently
via tools/list with 8s timeout
- Keep container checks (init/record/task/data_path) as fast builtins
- Graceful network setup failure in containerd handler (log warning
instead of killing task) for containerd-in-docker compatibility