## Summary
- make the external app-server time provider establish sleep deadlines
using `currentTime/read`
- poll the external clock once per second and complete `clock.sleep`
when the deadline is reached
- keep the system-clock timer and existing steer/agent-message
interruption behavior unchanged
## Why
This lets training control `clock.sleep` through its existing external
simulated clock without adding separate sleep/wake protocol methods.
## Testing
- `just fmt`
- `just test -p codex-app-server
external_sleep_polls_current_time_and_emits_items`
rka-oai
62c7f506d9