Handle OpenCode session events that carry the session ID under properties.info.id or properties.info.sessionID so background tasks and continuation hooks do not miss idle/error/delete events.
Add regression coverage for nested session.idle events completing background tasks and waking continuation hooks.
Reduce repeated session.idle work by reusing hook config loads across a short TTL and by retrying parent session lookup instead of permanently caching transient failures.
Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)
Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>
Apply the internal initiator marker to automated continuation, recovery, babysitter, stop-hook, and hook-message injections so Copilot attribution consistently sets x-initiator=agent for system-generated prompts.
YeonGyu-Kim