fix(tests): use isolated paths for remote branch test

Move remote.git and second_clone directories under git_repo
instead of git_repo.parent to prevent path collisions with
parallel test workers.

Assisted-By: 🤖 Claude Code

Author: rhuss

tests/test_timestamp_branches.py

@@ -514,8 +514,8 @@ def test_dry_run_accounts_for_remote_branches(self, git_repo: Path):
         """Dry-run queries remote refs via ls-remote (no fetch) for accurate numbering."""
         (git_repo / "specs" / "001-existing").mkdir(parents=True)
 
-        # Set up a bare remote and push
-        remote_dir = git_repo.parent / "remote.git"
+        # Set up a bare remote and push (use subdirs of git_repo for isolation)
+        remote_dir = git_repo / "test-remote.git"
         subprocess.run(
             ["git", "init", "--bare", str(remote_dir)],
             check=True, capture_output=True,
@@ -530,7 +530,7 @@ def test_dry_run_accounts_for_remote_branches(self, git_repo: Path):
         )
 
         # Clone into a second copy, create a higher-numbered branch, push it
-        second_clone = git_repo.parent / "second_clone"
+        second_clone = git_repo / "test-second-clone"
         subprocess.run(
             ["git", "clone", str(remote_dir), str(second_clone)],
             check=True, capture_output=True,