feat(node-registry): add support to send checkpoint/diffusion model to workflow

- Add capabilities parsing and validation for node registration
- Implement widget_names extraction from capabilities with type safety
- Add supports_lora boolean conversion in capabilities
- Include comfy_class fallback to node_type when missing
- Add new update_node_widget API endpoint for bulk widget updates
- Improve error handling and input validation for widget updates
- Remove unused parameters from node selector event setup function

These changes improve node metadata handling and enable dynamic widget management capabilities.

tests/routes/test_misc_routes.py

@@ -219,6 +219,78 @@ async def test_register_nodes_defaults_graph_name_to_none():
     assert stored_node["graph_name"] is None
 
 
+@pytest.mark.asyncio
+async def test_register_nodes_includes_capabilities():
+    node_registry = NodeRegistry()
+    handler = NodeRegistryHandler(
+        node_registry=node_registry,
+        prompt_server=FakePromptServer,
+        standalone_mode=False,
+    )
+
+    request = FakeRequest(
+        json_data={
+            "nodes": [
+                {
+                    "node_id": 9,
+                    "graph_id": "root",
+                    "type": "CheckpointLoaderSimple",
+                    "title": "Checkpoint Loader",
+                    "capabilities": {"supports_lora": False, "widget_names": ["ckpt_name", "", 42]},
+                }
+            ]
+        }
+    )
+
+    response = await handler.register_nodes(request)
+    payload = json.loads(response.text)
+
+    assert payload["success"] is True
+
+    registry = await node_registry.get_registry()
+    stored_node = next(iter(registry["nodes"].values()))
+    assert stored_node["capabilities"] == {"supports_lora": False, "widget_names": ["ckpt_name"]}
+    assert stored_node["widget_names"] == ["ckpt_name"]
+
+
+@pytest.mark.asyncio
+async def test_update_node_widget_sends_payload():
+    send_calls: list[tuple[str, dict]] = []
+
+    class RecordingPromptServer:
+        class Instance:
+            def send_sync(self, event, payload):
+                send_calls.append((event, payload))
+
+        instance = Instance()
+
+    handler = NodeRegistryHandler(
+        node_registry=NodeRegistry(),
+        prompt_server=RecordingPromptServer,
+        standalone_mode=False,
+    )
+
+    request = FakeRequest(
+        json_data={
+            "widget_name": "ckpt_name",
+            "value": "models/checkpoints/model.ckpt",
+            "node_ids": [{"node_id": 12, "graph_id": "root"}],
+        }
+    )
+
+    response = await handler.update_node_widget(request)
+    payload = json.loads(response.text)
+
+    assert response.status == 200
+    assert payload["success"] is True
+    assert send_calls == [
+        (
+            "lm_widget_update",
+            {"id": 12, "widget_name": "ckpt_name", "value": "models/checkpoints/model.ckpt", "graph_id": "root"},
+        )
+    ]
+
+
 @pytest.mark.asyncio
 async def test_update_lora_code_includes_graph_identifier():
     send_calls: list[tuple[str, dict]] = []