fix: pass /skill:control-agent as initial message so agent auto-starts

The --skill flag only adds the skill to the system prompt available skills
list (description + location). It does not inject the full content or trigger
an LLM turn. Adding the positional argument "/skill:control-agent" causes pi
to expand the skill command and send it as the first user message, which
triggers the startup checklist automatically.

Author: benvinegar

start.sh

@@ -25,4 +25,4 @@ export PI_SESSION_NAME="control-agent"
 
 # Start control-agent
 # --session-control: enables inter-session communication (handled by control.ts extension)
-pi --session-control --skill ~/.pi/agent/skills/control-agent
+pi --session-control --skill ~/.pi/agent/skills/control-agent "/skill:control-agent"