[feat] integrate asset browser with widget system (#5629)

## Summary

Add asset browser dialog integration for combo widgets with full
animation support and proper state management.

(Thank you Claude from saving me me from merge conflict hell on this
one.)

## Changes

- Widget integration: combo widgets now use AssetBrowserModal for
eligible asset types
- Dialog animations: added animateHide() for smooth close transitions
- Async operations: proper sequencing of widget updates and dialog
animations
- Service layer: added getAssetsForNodeType() and getAssetDetails()
methods
- Type safety: comprehensive TypeScript types and error handling
- Test coverage: unit tests for all new functionality
- Bonus: fixed the hardcoded labels in AssetFilterBar

Widget behavior:
- Shows asset browser button for eligible widgets when asset API enabled
- Handles asset selection with proper callback sequencing
- Maintains widget value updates and litegraph notification

## Review Focus

I will call out some stuff inline.

## Screenshots


https://github.com/user-attachments/assets/9d3a72cf-d2b0-445f-8022-4c49daa04637

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-5629-feat-integrate-asset-browser-with-widget-system-2726d73d365081a9a98be9a2307aee0b)
by [Unito](https://www.unito.io)

---------

Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: GitHub Action <action@github.com>

src/platform/assets/services/assetService.ts

@@ -1,6 +1,7 @@
 import { fromZodError } from 'zod-validation-error'
 
 import {
+  type AssetItem,
   type AssetResponse,
   type ModelFile,
   type ModelFolder,
@@ -127,10 +128,75 @@ function createAssetService() {
     )
   }
 
+  /**
+   * Gets assets for a specific node type by finding the matching category
+   * and fetching all assets with that category tag
+   *
+   * @param nodeType - The ComfyUI node type (e.g., 'CheckpointLoaderSimple')
+   * @returns Promise<AssetItem[]> - Full asset objects with preserved metadata
+   */
+  async function getAssetsForNodeType(nodeType: string): Promise<AssetItem[]> {
+    if (!nodeType || typeof nodeType !== 'string') {
+      return []
+    }
+
+    // Find the category for this node type using efficient O(1) lookup
+    const modelToNodeStore = useModelToNodeStore()
+    const category = modelToNodeStore.getCategoryForNodeType(nodeType)
+
+    if (!category) {
+      return []
+    }
+
+    // Fetch assets for this category using same API pattern as getAssetModels
+    const data = await handleAssetRequest(
+      `${ASSETS_ENDPOINT}?include_tags=${MODELS_TAG},${category}`,
+      `assets for ${nodeType}`
+    )
+
+    // Return full AssetItem[] objects (don't strip like getAssetModels does)
+    return (
+      data?.assets?.filter(
+        (asset) =>
+          !asset.tags.includes(MISSING_TAG) && asset.tags.includes(category)
+      ) ?? []
+    )
+  }
+
+  /**
+   * Gets complete details for a specific asset by ID
+   * Calls the detail endpoint which includes user_metadata and all fields
+   *
+   * @param id - The asset ID
+   * @returns Promise<AssetItem> - Complete asset object with user_metadata
+   */
+  async function getAssetDetails(id: string): Promise<AssetItem> {
+    const res = await api.fetchApi(`${ASSETS_ENDPOINT}/${id}`)
+    if (!res.ok) {
+      throw new Error(
+        `Unable to load asset details for ${id}: Server returned ${res.status}. Please try again.`
+      )
+    }
+    const data = await res.json()
+
+    // Validate the single asset response against our schema
+    const result = assetResponseSchema.safeParse({ assets: [data] })
+    if (result.success && result.data.assets?.[0]) {
+      return result.data.assets[0]
+    }
+
+    const error = result.error
+      ? fromZodError(result.error)
+      : 'Unknown validation error'
+    throw new Error(`Invalid asset response against zod schema:\n${error}`)
+  }
+
   return {
     getAssetModelFolders,
     getAssetModels,
-    isAssetBrowserEligible
+    isAssetBrowserEligible,
+    getAssetsForNodeType,
+    getAssetDetails
   }
 }