fix(plugins): keep rewound conversations on their retained branch (#8368)

Refresh direct plugin history from authoritative native persistence after conversation/combined rewind, matching the built-in providers' history refresh strategy. Reopen/replay rebuilds translation baselines, rewind tokens and child bindings while preserving outward subscriptions; file-only rewind stays unchanged.

Keep replay internal and replace the manager timeline after it completes. Preserve the committed native handle and close routing across refresh failures so retry and reload recover the retained branch.

The full native session reload is intentionally inefficient, pending a smarter timeline cut that restores translation state, reused IDs, children and permissions without reopening.

Closes #4667
Supersedes #4668 and the rewind-history proposal in #4754.

Verified with 72 targeted tests, green CI, and real OMP browser UI A/B/C -> rewind B -> replacement D with native history/timeline equality and a clean browser reload.

Co-authored-by: Matt Cowger <matt@cowger.us>
Co-authored-by: Omer Cohen <639682+omercnet@users.noreply.github.com>

public-docs/plugins/providers.md

@@ -287,6 +287,11 @@ Paseo refreshes an agent by closing its current provider session and opening it
 configuration and persistence. Re-read credentials, environment, global configuration, and MCP
 servers during `session.open`. There is no separate reload operation.
 
+Conversation and combined rewind require a core-restored session with persistence. After a
+successful rewind, Paseo closes the session and reopens its latest persistence value with
+`history: "replay"`. Publish the retained native branch before `session.ready`, including its
+children. File-only rewind keeps the current session and conversation history.
+
 Use `restoration: "core"` when Paseo can reopen a session from persistence. A provider-owned child
 uses `restoration: "parent"`; emit it as another `session.opened` event with `parentSessionId` and
 recreate it while restoring the parent.