Scrub references to older versions

tests/test_meta_contract_guards.py

@@ -69,6 +69,19 @@ _BASELINE_CLAIM = re.compile(
     r"\b(?:Current Baseline:\s*|current\s+|active\s+|canonical\s+)V(\d+(?:\.\d+)?)",
     re.IGNORECASE,
 )
+_LEGACY_VERSION_REFERENCE = re.compile(r"\b[Vv](4(?:\.\d+)?|5(?:\.\d+)?|6\.0)\b|test_v42_evidence|test_v45_candidates")
+LEGACY_VERSION_REFERENCE_EXCLUSIONS = frozenset(
+    {
+        ".github/workflows/quality-gate.yml",
+        "docs/data_migration.md",
+        "docs/requirements.md",
+        "docs/reviews",
+        "docs/roadmap_plan.md",
+        "docs/schema.md",
+        "src/transcription/db/operations.py",
+        "tests/test_meta_contract_guards.py",
+    }
+)
 
 
 def _declared_baseline() -> str:
@@ -112,6 +125,40 @@ def test_canonical_docs_declare_one_consistent_baseline():
     )
 
 
+def test_legacy_version_markers_are_scoped_to_allowed_historical_files():
+    """Version labels from older project baselines should not linger in active files.
+
+    Historical references are allowed only where the old version is the subject matter:
+    roadmap planning, dated reviews, stable requirement IDs, and explicit migration or
+    compatibility notes.
+    """
+    scanned: list[Path] = []
+    for root in (
+        PROJECT_ROOT / ".github",
+        PROJECT_ROOT / "docs",
+        PROJECT_ROOT / "src",
+        PROJECT_ROOT / "tests",
+    ):
+        scanned.extend(path for path in root.rglob("*") if path.suffix in {".md", ".py", ".yml", ".yaml"})
+    scanned.extend((PROJECT_ROOT / "AGENTS.md", PROJECT_ROOT / ".pre-commit-config.yaml"))
+
+    violations: dict[str, list[str]] = {}
+    for path in sorted(set(scanned)):
+        relative = path.relative_to(PROJECT_ROOT).as_posix()
+        if any(
+            relative == excluded or relative.startswith(f"{excluded}/")
+            for excluded in LEGACY_VERSION_REFERENCE_EXCLUSIONS
+        ):
+            continue
+        matches = sorted(
+            {match.group(0) for match in _LEGACY_VERSION_REFERENCE.finditer(path.read_text(encoding="utf-8"))}
+        )
+        if matches:
+            violations[relative] = matches
+
+    assert violations == {}, f"Legacy version markers remain in active files: {violations}"
+
+
 def test_active_contract_files_are_present():
     """Guard the guard: ensure all expected authority files are scanned."""
     missing = [path for path in ACTIVE_CONTRACT_FILES if not (PROJECT_ROOT / path).exists()]