[Bug]: Storage report doesn't see git worktrees nested one level deeper under ~/.t3/worktrees/<project>/ #25845

Before submitting

• I searched existing issues and did not find a duplicate.
• I included enough detail to reproduce or investigate the problem.

Area

apps/server

Steps to reproduce

mkdir -p ~/.t3/worktrees/<project>/replay
git -C <project-repo> worktree add ~/.t3/worktrees/<project>/replay/1376 -b replay-1376

Then open the storage cleanup report.

Expected behavior

The report shows replay/1376 as a git worktree that no thread uses. Alternatively, it warns that replay contains git worktrees.

Actual behavior

The report checks only one level below ~/.t3/worktrees/<project>/. replay is listed as "No thread uses this folder, and it isn't a git worktree", and the worktrees inside it never show up. On one machine, 7 registered worktrees were hidden this way inside two such folders. If these folders ever become deletable (#25844), deleting the parent would also delete the worktrees inside, uncommitted changes included, and leave stale entries in the repo's worktree list. That's the same failure mode as #23866.

Impact

Minor bug or occasional failure

Version or commit

0.1.3-nightly.20261027.3754

Environment

Ubuntu, Linux 7.0, desktop app.

Workaround

Run git worktree list in the project repo and remove the nested worktrees by hand.