Move takes_child/takes_parent information from Action to Resource (#2567)

Simplified Action by moving takes_child/takes_parent logic to Resource

- Removed InstanceResource - global actions are now simply those with resource_class=None
- Resource.parent_class - Replaced parent_name: str with parent_class: type[Resource] | None for direct class references
- Simplified Action dataclass - No more redundant fields, everything is derived from the Resource class structure
- Validation - The __init_subclass__ method now checks parent_class.parent_class to enforce the 2-level hierarchy

Closes #2563

tests/conftest.py

@@ -23,6 +23,10 @@ UNDOCUMENTED_PERMISSIONS = {
     "this_is_allowed_async",
     "this_is_denied_async",
     "no_match",
+    # Test actions from test_hook_register_actions_with_custom_resources
+    "manage_documents",
+    "view_document_collection",
+    "view_document",
 }
 
 _ds_client = None