feat(server): route workflow, hosting glue, and discovery by vcs kind

[THEjacob1000]

What Changed

GitWorkflowService routes every op by vcs kind, with a jj lane under apps/server/src/jj covering status, refs, remotes, workspaces, PRs and the stacked action. Both lanes satisfy one VcsWorkflowOps type so a signature change breaks both. Threads on a jj repo get workspaces instead of worktrees, and detection flips to jj first since a colocated repo answers yes to both probes.

Most of the diff is GitManager parameterised over vcs reads so jj reuses text generation and PR creation.

Why

The typed extension surface #2461 was held on, jj gets its own change, bookmark and workspace ops rather than git actions disabled. Remove and prune pick the driver from the path, not the project, so existing git worktrees on a colocated repo keep working. .git/hooks/pre-commit doesn't run under jj, known gap.

Stack

1. feat(vcs): jj driver, detection and process wrapper #11373
2. feat(server): jj-native checkpoints and review diffs #11382
3. This PR
4. feat(web,mobile): jj terminology and shared vcs action logic #11384

GitHub can't create stacked PRs from a fork, so the diff carries the PRs below. Review the top commit only.

Manual evidence

Manually exercised in the installed Linux desktop app, build 2a249f8e503a (the complete stack), using disposable repositories. These captures verify the integrated stack, not each lower PR in isolation.

Created a bookmark and committed from the app, then started an agent in a new jj workspace. Its file stayed outside the project checkout. Selected-file commit committed workspace.txt, left remaining.txt dirty and moved the workspace bookmark. The recording switches between working-copy and bookmark review to show the difference.

Remote pull/push, publishing, PR creation/preparation, divergence and conflict paths are still untested. Mobile workspace removal is pending.

Workspace creation and isolated agent edit

03-workspace.mp4

Selected-file commit and remaining changes

04-selected-file-commit.mp4

Checklist

• This PR is small and focused
• I explained what changed and why
• I included before/after screenshots for any UI changes
• I included a video for animation/interaction changes

Evidence captured with Codex; test turns used GPT-6 Astra.

[t3dotgg]

Note

🤖 GPT-6 Astra responding on behalf of Theo

We're closing this as part of a cleanup of old PRs. Thank you for the time and care you put into this contribution.

The current comparison includes 1,504 files and 486,812 changed lines, with conflicts in 551 files against the target branch. Much of that comparison comes from diverged base history, beyond the change described here. The latest implementation commit is from 2026-09-20.

At this point, regenerating a focused patch against the current intended base would be easier to review and maintain than updating this PR. We appreciate the problem report and the work already done; this thread will remain available as a reference. If you revisit it, please confirm the current direction with us and link a fresh, focused PR back here.