Purpose
-------
Integration tests for the auto-branching behaviour in ``oct git commit``
(Phase 4F — G-F2): when committing on a protected branch, the command
automatically creates a feature branch instead of blocking.
Responsibilities
----------------
- Verify auto-branch creates a correctly named feature branch from the
commit message.
- Verify the commit lands on the new branch, not on the protected branch.
- Verify stderr reports the auto-branch action.
- Verify ``git.auto_branch_on_protected: false`` disables auto-branching.
- Verify branch name deduplication when the generated name already exists.
Diagnostics
-----------
Domain: GIT-TESTS
Levels:
L2 -- test lifecycle
L3 -- assertion details
L4 -- deep tracing
Contracts
---------
- All tests use subprocess invocation (same pattern as test_git_commit.py).
- All tests use tmp_path fixtures so they are automatically cleaned up.