refactor: extract createAssetWidget to shared factory, remove # privates

- Extract createAssetWidget factory to src/platform/assets/utils/
- Refactor useComboWidget.ts to use the shared factory
- Simplify PrimitiveNode to use shared factory
- Convert JS # privates to underscore convention
- Add knip ignore for isAssetWidget (litegraph public API)

Amp-Thread-ID: https://ampcode.com/threads/T-019c0839-bbdc-754a-9d3b-151417058ded
Co-authored-by: Amp <amp@ampcode.com>

src/platform/assets/utils/createAssetWidget.ts

@@ -0,0 +1,88 @@
+import { t } from '@/i18n'
+import type { LGraphNode } from '@/lib/litegraph/src/litegraph'
+import type {
+  IBaseWidget,
+  IWidgetAssetOptions
+} from '@/lib/litegraph/src/types/widgets'
+import { useAssetBrowserDialog } from '@/platform/assets/composables/useAssetBrowserDialog'
+import {
+  assetFilenameSchema,
+  assetItemSchema
+} from '@/platform/assets/schemas/assetSchema'
+import { getAssetFilename } from '@/platform/assets/utils/assetMetadataUtils'
+
+interface CreateAssetWidgetParams {
+  /** The node to add the widget to */
+  node: LGraphNode
+  /** The widget name */
+  widgetName: string
+  /** The node type to show in asset browser (may differ from node.comfyClass for PrimitiveNode) */
+  nodeTypeForBrowser: string
+  /** Default value for the widget */
+  defaultValue?: string
+  /** Callback when widget value changes */
+  onValueChange?: (
+    widget: IBaseWidget,
+    newValue: string,
+    oldValue: unknown
+  ) => void
+}
+
+/**
+ * Creates an asset widget that opens the Asset Browser dialog for model selection.
+ * Used by both regular nodes (via useComboWidget) and PrimitiveNode.
+ *
+ * @param params - Configuration for the asset widget
+ * @returns The created asset widget
+ */
+export function createAssetWidget(
+  params: CreateAssetWidgetParams
+): IBaseWidget {
+  const { node, widgetName, nodeTypeForBrowser, defaultValue, onValueChange } =
+    params
+
+  const displayLabel = defaultValue ?? t('widgets.selectModel')
+  const assetBrowserDialog = useAssetBrowserDialog()
+
+  async function openModal(widget: IBaseWidget) {
+    await assetBrowserDialog.show({
+      nodeType: nodeTypeForBrowser,
+      inputName: widgetName,
+      currentValue: widget.value as string,
+      onAssetSelected: (asset) => {
+        const validatedAsset = assetItemSchema.safeParse(asset)
+
+        if (!validatedAsset.success) {
+          console.error(
+            'Invalid asset item:',
+            validatedAsset.error.errors,
+            'Received:',
+            asset
+          )
+          return
+        }
+
+        const filename = getAssetFilename(validatedAsset.data)
+        const validatedFilename = assetFilenameSchema.safeParse(filename)
+
+        if (!validatedFilename.success) {
+          console.error(
+            'Invalid asset filename:',
+            validatedFilename.error.errors,
+            'for asset:',
+            validatedAsset.data.id
+          )
+          return
+        }
+
+        const oldValue = widget.value
+        widget.value = validatedFilename.data
+        onValueChange?.(widget, validatedFilename.data, oldValue)
+      }
+    })
+  }
+
+  const options: IWidgetAssetOptions = { openModal }
+
+  return node.addWidget('asset', widgetName, displayLabel, () => {}, options)
+}