hwp-pid: Agent crashes if device offline at startup

When the agent is started, if the device is offline, the main process will crash:

2026-03-12T18:07:31+0000 startup-op: launching main
2026-03-12T18:07:31+0000 start called for main
2026-03-12T18:07:31+0000 main:0 Status is now "starting".
2026-03-12T18:07:31+0000 main:0 Status is now "running".
2026-03-12T18:07:33+0000 Failed to connect to device at 192.168.12.22:2001
2026-03-12T18:07:33+0000 Failed to connect to device at 192.168.12.22:2001
2026-03-12T18:07:33+0000 Failed to connect to device at 192.168.12.22:2001
2026-03-12T18:07:33+0000 main:0 CRASH: [Failure instance: Traceback: <class 'RuntimeError'>: Could not connect to PID controller
/opt/venv/lib/python3.10/site-packages/twisted/python/threadpool.py:269:inContext
/opt/venv/lib/python3.10/site-packages/twisted/python/threadpool.py:285:<lambda>
/opt/venv/lib/python3.10/site-packages/twisted/python/context.py:117:callWithContext
/opt/venv/lib/python3.10/site-packages/twisted/python/context.py:82:callWithContext
/opt/venv/lib/python3.10/site-packages/ocs/ocs_agent.py:1074:_running_wrapper
/opt/venv/lib/python3.10/site-packages/socs/agents/hwp_pid/agent.py:181:main
/opt/venv/lib/python3.10/site-packages/socs/agents/hwp_pid/drivers/pid_controller.py:50:__init__
/opt/venv/lib/python3.10/site-packages/socs/agents/hwp_pid/drivers/pid_controller.py:78:_establish_connection
]
2026-03-12T18:07:33+0000 main:0 Status is now "done".

socs version: v0.6.0

Start with socs/agents/hwp_pid/agent.py at main and follow the connection setup into drivers/pid_controller.py, especially init and _establish_connection. Reproduce startup with the device offline and trace the RuntimeError shown in the report. Done should be verified by confirming the agent no longer crashes during offline startup and by adding or updating a regression test if the project has coverage for this path.