Add resume_agent collab tool (#10903)

Summary
- add the new resume_agent collab tool path through core, protocol, and
the app server API, including the resume events
- update the schema/TypeScript definitions plus docs so resume_agent
appears in generated artifacts and README
- note that resumed agents rehydrate rollout history without overwriting
their base instructions

Testing
- Not run (not requested)

codex-rs/mcp-server/src/codex_tool_runner.rs

@@ -364,6 +364,8 @@ async fn run_codex_tool_session_inner(
                     | EventMsg::CollabWaitingEnd(_)
                     | EventMsg::CollabCloseBegin(_)
                     | EventMsg::CollabCloseEnd(_)
+                    | EventMsg::CollabResumeBegin(_)
+                    | EventMsg::CollabResumeEnd(_)
                     | EventMsg::DeprecationNotice(_) => {
                         // For now, we do not do anything extra for these
                         // events. Note that