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

vue-widgets/vite.config.mts

@@ -21,7 +21,8 @@ export default defineConfig({
         },
         rollupOptions: {
             external: [
-                '../../../scripts/app.js'
+                '../../../scripts/app.js',
+                '../loras_widget.js'
             ],
             output: {
                 dir: '../web/comfyui/vue-widgets',