chore(p0): retire regress, the skill router, the module audit tool and vocabulary.sc

Off every active line (PATHFINDER-2026-10-13/03-unified-proposal.md, cuts).
Deleted: src/openultrasast/regress/ and the deep-mode REGRESS branch (deep
now records a regress_retired degradation and equals standard; proof is the
search-with-proof arm's job), the sandbox docker runner and probe that only
regress used, --fail-on worth-fixing, RegressConfig, the two ledger helpers
only regress called; skills.py and index.py with the hunter pool's skill
routing; model/audit.py; cpg/queries/vocabulary.sc with
benchmarks/push/ontology_gap.py. Docs and the scan skill describe the
retirement. Net: 3,895 lines deleted, 86 added. Targeted tests: 180 passed,
28 skipped; 3,331 tests collect.

Co-Authored-By: Claude Fable 5.1 <[email protected]>

tests/test_tool_hunter.py

@@ -198,8 +198,6 @@ def _latest_run(repo: Path) -> Path:
 def _guard_docker(monkeypatch: pytest.MonkeyPatch) -> list[list[str]]:
     import subprocess
 
-    from openultrasast.sandbox import runner as sandbox_runner
-
     docker_argv: list[list[str]] = []
     original_run = subprocess.run
 
@@ -210,11 +208,7 @@ def _guard_docker(monkeypatch: pytest.MonkeyPatch) -> list[list[str]]:
             raise AssertionError(f"hunter scan test must not start docker: {argv}")
         return original_run(command, *args, **kwargs)
 
-    def fail(*args: object, **kwargs: object) -> object:
-        raise AssertionError("hunter scan test must not use DockerCliRunner")
-
     monkeypatch.setattr(subprocess, "run", guarded_run)
-    monkeypatch.setattr(sandbox_runner.DockerCliRunner, "run", fail)
     return docker_argv