Adapts main's changes to the single asynchronous timeline owner:
- The subscribe freshness check (#9175) awaits the loaded timeline head and
compares the client's cursor against the epoch that client sees, so legacy
clients compare against their derived epoch after a rewind.
- History reads (#8737) pass purpose "history" when an agent with no stored
timeline must be loaded; stored history is still read without the provider.
- Background work clears on reload, close and parent delete next to the
async provider-child cancellation.
- Claude steered-message rewinds (#8372) report an at-target cut. Codex keeps
main's saved thread id alongside the reported cut.
- Plugin rewinds (#8368) return an unreported outcome; a failed replay after
the native revert leaves the rewind for the reload to settle rather than a
retry. Manager-level rewinds target the timeline row's message id.
- Main's tests read the timeline asynchronously, and wait for the provider to
receive a prompt instead of assuming it arrives in the dispatch tick.
Mohamed Boudra
457d8d6ec5