Module tick 

Core tick loop phases.

The engine ticks every ~10 seconds. Each tick runs six sequential phases:

1. Poll tmux for finished sessions
2. Recover stuck in-progress tasks
3. Route and dispatch:
   • 3a. Route new tasks to agents
   • 3b. Dispatch routed tasks (spawn agents)
4. Unblock parents whose children are all done
5. Run cron job scheduler