fix: handle bare repos in branch creation and checkout

- Fall back to symbolic-ref when checkout --orphan fails on bare repos\n- Fall back to symbolic-ref when checkout fails on bare repos\n- Make get_current_branch handle bare repos with unborn branches\n- Add integration tests for bare repo branch operations\n\nQuality gates: pytest integration tests (12 passed)

apps/api/tests/integration/test_git_control.py

@@ -70,6 +70,20 @@ def test_get_current_branch_handles_unborn_main() -> None:
         assert get_current_branch(tmpdir) == "main"
 
 
+def test_create_branch_on_bare_repo_with_no_commits() -> None:
+    with tempfile.TemporaryDirectory() as tmpdir:
+        os.system(f"git init --bare {tmpdir}/bare.git >/dev/null 2>&1")
+        create_branch(f"{tmpdir}/bare.git", "main")
+        assert get_current_branch(f"{tmpdir}/bare.git") == "main"
+
+
+def test_checkout_branch_on_bare_repo_with_no_commits() -> None:
+    with tempfile.TemporaryDirectory() as tmpdir:
+        os.system(f"git init --bare {tmpdir}/bare.git >/dev/null 2>&1")
+        checkout_branch(f"{tmpdir}/bare.git", "main")
+        assert get_current_branch(f"{tmpdir}/bare.git") == "main"
+
+
 class TestBranchOperations:
     """Tests for branch management functions."""