fix(worktree): track explicit remote-only branch (#31645)

* fix(worktree): track explicit remote branch

* test(worktree): cover remote branch path retry

* fix(worktree): resolve cached remote branches canonically

* fix(git): retain commit validation in bounded ref probes

* fix(worktree): preserve selected remote identity during creation

* test(worktree): count cached resolver Git work during path retries

* Fix branch intent state in composer source fixture

* Make Git and daemon regression fixtures portable

* Use the selected base for existing branch creation

---------

Co-authored-by: Brennan Benson <79079362+brennanb2025@users.noreply.github.com>

src/main/git/worktree-add-remote-branch-upstream-real-git.test.ts

@@ -78,6 +78,9 @@ it('tracks the remote branch it was created from, and nothing else', async () =>
   const fixPath = join(root, 'fix')
   await addWorktree(repo, fixPath, 'alex/fix', 'origin/alex/fix')
   expect(await upstreamOf(fixPath, 'alex/fix')).toBe('origin/alex/fix')
+  const ref = 'refs/remotes/origin/alex/fix'
+  expect(await git(fixPath, 'config', '--get', 'branch.alex/fix.base')).toBe(ref)
+  expect(await git(fixPath, 'config', '--get', 'push.autoSetupRemote')).toBe('true')
   expect(await git(fixPath, 'rev-parse', 'HEAD')).toBe(
     await git(repo, 'rev-parse', 'refs/remotes/origin/alex/fix')
   )
@@ -112,4 +115,10 @@ it('tracks the remote branch when a prepared checkout finalizes the create', asy
     prepared.lockReason
   )
   expect(await upstreamOf(fixPath, 'alex/fix')).toBe('origin/alex/fix')
+  const ref = 'refs/remotes/origin/alex/fix'
+  expect(await git(fixPath, 'config', '--get', 'branch.alex/fix.base')).toBe(ref)
+  expect(await git(fixPath, 'config', '--get', 'push.autoSetupRemote')).toBe('true')
+  expect(await git(fixPath, 'rev-parse', 'HEAD')).toBe(
+    await git(repo, 'rev-parse', 'refs/remotes/origin/alex/fix')
+  )
 })