fix(coding-agent): handle stale extension contexts

fixes #3606

packages/coding-agent/CHANGELOG.md

@@ -18,8 +18,14 @@
 - Added searchable auth provider login flow with fuzzy filtering in the provider selector ([#3572](https://github.com/badlogic/pi-mono/pull/3572) by [@mitsuhiko](https://github.com/mitsuhiko))
 - Added GPT-5.5 Codex model
 
+### Changed
+
+- Improved stale extension context errors after session replacement or reload to tell extension authors to avoid captured `pi`/command `ctx` and use `withSession` for post-replacement work.
+
 ### Fixed
 
+- Fixed the handoff extension example to use the replacement-session context after creating a new session, avoiding stale `ctx` errors when it installs the generated prompt ([#3606](https://github.com/badlogic/pi-mono/issues/3606))
+- Fixed session replacement and `/quit` teardown ordering to run host-owned extension UI cleanup synchronously after `session_shutdown` handlers complete but before invalidating the old extension context, preventing stale extension UI from rendering against a disposed session.
 - Fixed crash on `/quit` when an extension registers a custom footer whose `render()` accesses `ctx`, by tearing down extension-provided UI before invalidating the extension runner during shutdown ([#3595](https://github.com/badlogic/pi-mono/issues/3595))
 - Fixed auto-retry to treat Bedrock/Smithy HTTP/2 transport failures like `http2 request did not get a response` as transient errors, so the agent retries automatically instead of waiting for a manual nudge ([#3594](https://github.com/badlogic/pi-mono/issues/3594))
 - Fixed the CLI/SDK tool-selection split so `--no-builtin-tools` and `createAgentSession({ noTools: "builtin" })` disable only built-in default tools while keeping extension/custom tools enabled, instead of falling through to the same "disable everything" path as `--no-tools` ([#3592](https://github.com/badlogic/pi-mono/issues/3592))