Add optional system and tools fields to DelegatedChildSessionBootstrap
so callers can stash the original delegated context alongside retry
parts. Backward compatible - existing callers stay unchanged.
Preserve delegated child prompt/bootstrap metadata for early runtime fallback before OpenCode has persisted the first user turn. Bind prompt gate calls to the SDK session receiver and keep completed background task lookup visible across plugin manager instances.
Capture delegated child-session retry context before the first prompt so fallback recovery still works when session history is empty. Align background and sync launch paths around the same bootstrap contract, clear session-scoped fallback state on every terminal path, and lock the behavior with regression coverage for first-prompt retries, exhaustion, isolation, and cleanup.
Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)
Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>
YeonGyu-Kim