## Summary
Forgot to remove this in #1869 last night! Too much of a performance hit
on the main thread. We can bring it back via an async thread on startup.
## Summary
Includes a new user message in the api payload which provides useful
environment context for the model, so it knows about things like the
current working directory and the sandbox.
## Testing
Updated unit tests
## Summary
Have seen these tests flaking over the course of today on different
boxes. `wiremock` seems to be generally written with tokio/threads in
mind but based on the weird panics from the tests, let's see if this
helps.
- MCP server: add send-user-message tool to send user input to a running
Codex session
- Added an integration tests for the happy and sad paths
Changes:
• Add tool definition and schema.
• Expose tool in capabilities.
• Route and handle tool requests with validation.
• Tests for success, bad UUID, and missing session.
follow‑ups
• Listen path not implemented yet; the tool is present but marked “don’t
use yet” in code comments.
• Session run flag reset: clear running_session_id_set appropriately
after turn completion/errors.
This is the third PR in a stack.
Stack:
Final: #1686
Intermediate: #1751
First: #1750
