Support Jujutsu (jj) workspaces in the desktop review pane

[hamishgts]

Feature request

Please support Jujutsu (jj) workspaces in the Codex desktop review pane. JJ workspaces contain .jj metadata but no .git directory, which appears to prevent Codex from enabling the pane.

Current behavior

The review pane is available in my main colocated JJ/Git repository, but unavailable in additional JJ workspaces belonging to the same repository.

Codex appears to rely on Git repository detection to enable the review pane.

Expected behavior

Codex should recognize JJ workspaces and allow users to inspect their changes in the review pane (in exactly the same way that is already possible in the main colocated JJ/Git repository).

In the main colocated JJ repo it is also currently possible to compare between git branches a.k.a jj bookmarks which is very useful and it would be good if this also works from a JJ workspace in the same way.

A read-only implementation to enable just this would be useful on it's own as a first step without having to implement full Jujutsu VSC support as covered by these raised requests:

• Codex app: support Jujutsu (jj) workspaces or custom worktree backend #26648
• Feature Request: Support for Additional VCS (e.g., Jujutsu) #1327

Why this matters

JJ workspaces provide isolated checkouts for concurrent tasks. The current Git requirement prevents users from accessing Codex’s native diff viewer in those workspaces, even when the underlying repository uses Git storage.

Reproduction

1. Open a colocated JJ/Git repository in Codex.
2. Confirm that the review pane is available.
3. Create an additional workspace with jj workspace add ../jj-workspace.
4. Open that workspace as a project in Codex.
5. Observe that the review pane is unavailable, although jj status and jj diff --git work.

[hamishgts]

As of JJ version v0.46 - JJ workspaces can now also be colocated with git (as a git worktree) - so the codex review panel is now visible for them 🎉