Add defensible orphaned audio detection

tests/test_web.py

@@ -37,6 +37,8 @@ def test_web_analysis_uses_production_health_pipeline(tmp_path):
     assert result["details"]["old_crate_references"]["items"][0]["crate"]
     assert result["details"]["suggested_matches"]["total"] == 0
     assert result["details"]["unused_tracks"]["total"] == 1
+    assert result["orphan_candidates"] == 0
+    assert result["details"]["orphan_candidates"]["assessed"] is True
 
 
 def test_web_analysis_rejects_missing_folders(tmp_path):
@@ -58,6 +60,7 @@ def test_web_static_assets_are_declared_and_packaged():
     html = (asset_root / "index.html").read_text(encoding="utf-8")
     assert "Missing tracks in Serato" in html
     assert "Old crate references" in html
+    assert "Possible orphan files" in html
     assert "Choose a diagnostic" in html
     assert "Backup recovery" in html
     assert "Here’s exactly what will happen" in html