进一步清理代码和注册过程

tests/unit/test_registry_unified_handler_lookup.py

@@ -22,7 +22,7 @@ class RegistryLookupApiHandler:
     __test__ = False
 
 
-class RegistryLookupDbHandler:
+class RegistryLookupCustomHandler:
     __test__ = False
 
 
@@ -33,7 +33,7 @@ def test_registry_supports_unified_handler_lookup() -> None:
         reg = DomainRegistry.get_registration(node_type)
         reg.jsonl_handler_class = RegistryLookupJsonlHandler
         reg.api_handler_class = RegistryLookupApiHandler
-        reg.db_handler_class = RegistryLookupDbHandler
+        reg.handler_classes["custom"] = RegistryLookupCustomHandler
     else:
         DomainRegistry.register(
             node_type=node_type,
@@ -41,9 +41,9 @@ def test_registry_supports_unified_handler_lookup() -> None:
             node_class=RegistryLookupNode,
             jsonl_handler_class=RegistryLookupJsonlHandler,
             api_handler_class=RegistryLookupApiHandler,
-            db_handler_class=RegistryLookupDbHandler,
         )
+        DomainRegistry.register_handler(node_type, "custom", RegistryLookupCustomHandler)
 
     assert DomainRegistry.get_handler(node_type, "jsonl") is RegistryLookupJsonlHandler
     assert DomainRegistry.get_handler(node_type, "api") is RegistryLookupApiHandler
-    assert DomainRegistry.get_handler(node_type, "db") is RegistryLookupDbHandler
+    assert DomainRegistry.get_handler(node_type, "custom") is RegistryLookupCustomHandler