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.
- Extract types to types.ts
- Extract constants to constants.ts
- Extract session ID helpers to session-id.ts
- Extract recovery logic to recovery.ts
hook.ts reduced from 331 to 164 LOC
Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)
Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>
YeonGyu-Kim