fluxAnimation shows "Waiting" after completion due to stuck analysis ops

[robnagler]

When DockerDriver._do_agent_start fails with:

AttributeError: 'NoneType' object has no attribute 'name'
docker.py:247: self.driver_details.pkupdate(host=self.host.name)

self.host is None, so the agent never starts. Subsequent analysis ops for the same compute job queue on op_slot and wait forever. The simulation UI shows "Waiting" indefinitely after the compute phase completes.

Root causes:

• docker.py: self.host can be None in _do_agent_start; needs a guard
• job_supervisor.py: analysis ops queued behind a failed op_slot never time out or get cleaned up