refactor(pchome): extract backlog policy and evidence modules

tests/test_codebase_modularization_performance_service.py

@@ -28,8 +28,8 @@ def test_inventory_generates_complete_prioritized_work_items():
     assert all(item["work_item_id"] for item in result["python_work_items"])
     by_path = {item["path"]: item for item in result["python_work_items"]}
     assert by_path["routes/openclaw_bot_routes.py"]["status"] == "in_progress"
-    assert by_path["services/pchome_mapping_backlog_service.py"]["status"] == "not_started"
-    assert summary["work_item_status_counts"]["in_progress"] == 3
+    assert by_path["services/pchome_mapping_backlog_service.py"]["status"] == "in_progress"
+    assert summary["work_item_status_counts"]["in_progress"] == 4
     assert sum(summary["work_item_status_counts"].values()) == (
         summary["large_python_module_count"] + summary["large_frontend_asset_count"]
     )

tests/test_pchome_mapping_backlog_modularization.py

@@ -0,0 +1,45 @@
+from pathlib import Path
+
+from services import pchome_mapping_backlog_service as compatibility_facade
+from services.pchome_mapping_backlog import contracts, evidence, policies
+
+
+ROOT = Path(__file__).resolve().parents[1]
+
+
+def test_policy_registry_is_extracted_without_changing_legacy_exports():
+    assert len(policies.__all__) == 96
+    assert compatibility_facade.BACKLOG_POLICY == policies.BACKLOG_POLICY
+    assert (
+        compatibility_facade.AUTO_POLICY_DB_APPLY_CONTROLLED_DRY_RUN_PACKAGE_POLICY
+        == policies.AUTO_POLICY_DB_APPLY_CONTROLLED_DRY_RUN_PACKAGE_POLICY
+    )
+    assert compatibility_facade.PCHOME_FETCH_ALLOWED_DOMAIN == "24h.pchome.com.tw"
+
+
+def test_evidence_and_contract_functions_keep_legacy_import_identity():
+    assert (
+        compatibility_facade.parse_pchome_product_page_evidence_html
+        is evidence.parse_pchome_product_page_evidence_html
+    )
+    assert compatibility_facade.parse_unit_package_basis is evidence.parse_unit_package_basis
+    assert (
+        compatibility_facade._ai_exception_compatibility_fields
+        is contracts._ai_exception_compatibility_fields
+    )
+
+
+def test_extracted_unit_parser_preserves_ai_exception_and_no_write_contract():
+    parsed = compatibility_facade.parse_unit_package_basis("理膚寶水 B5 40ml x2 超值組")
+
+    assert parsed["estimated_total_quantity"] == 80
+    assert parsed["ai_exception_required"] is True
+    assert parsed["primary_human_gate_count"] == 0
+    assert parsed["writes_database"] is False
+    assert parsed["fetches_external_sites"] is False
+
+
+def test_legacy_facade_is_smaller_after_first_p0_extraction():
+    facade = ROOT / "services/pchome_mapping_backlog_service.py"
+
+    assert sum(1 for _ in facade.open(encoding="utf-8")) < 44_300