Codex Desktop: let users choose the working path from the chat composer before starting a thread

What variant of Codex are you using?

App (Desktop, macOS)

What feature would you like to see?

In Codex Desktop, allow choosing or changing the local working path directly from the chat composer when starting a new thread.

Current friction:

• When the thread list is sorted by Latest, it is hard to quickly tell which project or workspace a thread belongs to.
• It is easy to start a new conversation in the wrong project because the active workspace is not obvious enough at send time.
• The current workaround is to back out, inspect the project context, and retry, which is slow and error-prone.

Proposed UX:

• Add a visible workspace/path picker near the chat input for new threads, or before the first message is sent.
• Show the full selected local path in the composer or thread header before the session is created.
• Allow searching recent folders/workspaces from the same picker.
• If the current workspace is ambiguous, require an explicit selection before creating the thread.
• Optionally show repo name, branch, and absolute path in the new-thread surface so sorting by Latest does not hide project context.

Expected outcome:
Users can confirm the exact project before sending the first prompt, instead of noticing only after Codex has already created the session in the wrong place.

Additional information

Related but not equivalent:

• #16754 is about misleading workspace defaults and silent failures.
• #16187 is about new threads landing in the wrong workspace.
• #12464 is about switching cwd inside an existing CLI session.

This request is specifically about the Desktop app's pre-send/new-thread UX. It would reduce accidental work in the wrong repo, which is more than a navigation issue because it can lead to edits or commands being run in the wrong project.