feat: add LoraDemoNode and LoraRandomizerNode with documentation

- Import and register two new nodes: LoraDemoNode and LoraRandomizerNode
- Update import exception handling for better readability with multi-line formatting
- Add comprehensive documentation file `docs/custom-node-ui-output.md` for UI output usage in custom nodes
- Ensure proper node registration in NODE_CLASS_MAPPINGS for ComfyUI integration
- Maintain backward compatibility with existing node structure and import fallbacks

web/comfyui/lora_demo_widget.js

@@ -0,0 +1,40 @@
+import { app } from "../../../scripts/app.js";
+
+app.registerExtension({
+  name: "LoraManager.LoraDemo",
+
+  // Hook into node creation
+  async nodeCreated(node) {
+    if (node.comfyClass !== "Lora Demo (LoraManager)") {
+      return;
+    }
+
+    // Store original onExecuted
+    const originalOnExecuted = node.onExecuted?.bind(node);
+
+    // Override onExecuted to handle UI updates
+    node.onExecuted = function(output) {
+      // Check if output has loras data
+      if (output?.loras && Array.isArray(output.loras)) {
+        console.log("[LoraDemoNode] Received loras data from backend:", output.loras);
+
+        // Find the loras widget on this node
+        const lorasWidget = node.widgets.find(w => w.name === 'loras');
+
+        if (lorasWidget) {
+          // Update widget value with backend data
+          lorasWidget.value = output.loras;
+
+          console.log(`[LoraDemoNode] Updated widget with ${output.loras.length} loras`);
+        } else {
+          console.warn("[LoraDemoNode] loras widget not found on node");
+        }
+      }
+
+      // Call original onExecuted if it exists
+      if (originalOnExecuted) {
+        return originalOnExecuted(output);
+      }
+    };
+  }
+});