chore(#681): preserve dirty control-checkout WIP from PR #680 review session

Moves the three uncommitted test-isolation changes off the root/control
checkout into a dedicated issue-681 branch, per issue #681 recovery path
(AC2: retained test-isolation changes land on a dedicated issue branch
with review; never smuggled into #604/PR #680).

Preserved as-is (NOT endorsed) for review:
- gitea_mcp_server.py: test-mode early return in _verify_role_mutation_workspace
- issue_lock_worktree.py: strips *.py lines from porcelain under pytest/unittest
- tests/test_preflight_read_survival.py: patches out branches-only + root-checkout guards

These weaken workspace/dirtiness guards under test and require review before
any adoption; committed here only to restore the control checkout to clean
master without discarding unique work.

Refs #681

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>

gitea_mcp_server.py

@@ -728,6 +728,8 @@ def _verify_role_mutation_workspace(
     task: str | None = None,
 ) -> str:
     """Bind reviewer/merger mutations to the active namespace workspace (#510)."""
+    if _preflight_in_test_mode():
+        return _resolve_preflight_workspace_path(worktree_path)
 
     # Check running runtimes to prevent stale mutations
     try: