test(cruft_removal): Phase 9 invariant tests (4 tests; verify wrappers + tests)

Phase 9 (Patch Phase) invariant tests per Tier 1's spec.md §12.6:

1. test_phase9_audit_legacy_wrappers_finds_zero: 0 legacy wrappers
2. test_phase9_baseline_tests_31_of_31_pass: 31/31 baseline tests pass
3. test_phase9_gui_2_wrappers_gone: _detect_refresh_rate_win32 +
   _resolve_font_path deleted from src/gui_2.py
4. test_phase9_rag_engine_chunk_code_gone: RAGEngine._chunk_code deleted

The 3 wrappers Tier 1 said were remaining in the tier-2-clone
(per the remote-tracking branch at 8f6d044d) are actually all
gone in the merged branch state. The 7 originally-failing baseline
tests all pass.

This is the Phase 9 task 5 deliverable: invariant test that verifies
the 3 wrappers and 7 tests with REAL pytest output, not claimed counts.

Test result: 4/4 Phase 9 tests pass. Total cruft_removal tests: 18.

tests/test_cruft_removal.py

@@ -175,4 +175,58 @@ def test_phase6_audit_finds_zero_wrappers_in_src():
     )
     assert "Found 0 legacy wrappers" in r.stdout, (
         f"expected 0 legacy wrappers in src/, but audit found:\n{r.stdout[:500]}"
+    )
+
+
+# ============ Phase 9 (Patch Phase — corrective verification) ============
+
+def test_phase9_audit_legacy_wrappers_finds_zero():
+    """Phase 9 invariant: scripts/audit_legacy_wrappers.py finds 0 legacy wrappers in src/.
+
+    The 3 wrappers Tier 1 said were remaining in the tier-2-clone
+    (_detect_refresh_rate_win32, _resolve_font_path, _chunk_code) are
+    actually all gone in the merged branch state.
+    """
+    r = subprocess.run(
+        ["uv", "run", "python", "scripts/audit_legacy_wrappers.py"],
+        capture_output=True, text=True,
+    )
+    assert "Found 0 legacy wrappers" in r.stdout, (
+        f"Phase 9 invariant: expected 0 legacy wrappers; audit found:\n{r.stdout[:500]}"
+    )
+
+
+def test_phase9_baseline_tests_31_of_31_pass():
+    """Phase 9 invariant: the 7 originally-failing baseline tests all pass.
+
+    Tier 1's spec said 7 tests were failing; the merged branch state
+    has all 31 tests passing. The 7 scaffolding failures were fixed in
+    Phase 1 (synthesized PHASE1_AUDIT_BASELINE.json from inventory docs).
+    """
+    r = subprocess.run(
+        ["uv", "run", "python", "-m", "pytest", "tests/test_baseline_result.py",
+         "--tb=no", "-q"],
+        capture_output=True, text=True,
+    )
+    assert "31 passed" in r.stdout, (
+        f"Phase 9 invariant: expected 31/31 baseline tests to pass; got:\n{r.stdout[-500:]}"
+    )
+
+
+def test_phase9_gui_2_wrappers_gone():
+    """Phase 9 invariant: gui_2._detect_refresh_rate_win32 + _resolve_font_path are DELETED."""
+    from src import gui_2
+    assert not hasattr(gui_2, "_detect_refresh_rate_win32"), (
+        "_detect_refresh_rate_win32 wrapper STILL EXISTS (should be deleted)"
+    )
+    assert not hasattr(gui_2, "_resolve_font_path"), (
+        "_resolve_font_path wrapper STILL EXISTS (should be deleted)"
+    )
+
+
+def test_phase9_rag_engine_chunk_code_gone():
+    """Phase 9 invariant: RAGEngine._chunk_code is DELETED."""
+    from src.rag_engine import RAGEngine
+    assert not hasattr(RAGEngine, "_chunk_code"), (
+        "RAGEngine._chunk_code STILL EXISTS (should be deleted)"
     )