codex: migrate (more) app-server thread history reads to ThreadStore (#20575)

Migrate token usage replay, rollback responses, and detached review
setup (a special case of forking) to be served from ThreadStore reads
rather direct rollout files.

- replay restored token usage from already-loaded `RolloutItem` history
instead of reopening `Thread.path`
- rebuild rollback responses from loaded `ThreadStore` snapshots and
history
- start detached reviews from store-backed parent history and stored
review-thread metadata
- remove obsolete app-server rollout-summary helper code that became
dead after the store-backed migration
- preserve response/notification ordering for resume, fork, rollback,
and detached review flows
- add integration test coverage for the affected paths

codex-rs/app-server/src/message_processor.rs

@@ -409,7 +409,6 @@ impl MessageProcessor {
             thread_state_manager,
             thread_watch_manager,
             thread_list_state_permit,
-            state_db.clone(),
         );
         if matches!(plugin_startup_tasks, crate::PluginStartupTasks::Start) {
             // Keep plugin startup warmups aligned at app-server startup.