feat(ComboWidget): add ability to have mapped inputs (#6585)

## Summary

1. Add a `getOptionLabel` option to `ComboWidget` so users of it can map
of custom labels to widget values. (e.g., `"My Photo" ->
"my_photo_1235.png"`).
2. Utilize this ability in Cloud environment to map user uploaded
filenames to their corresponding input asset.
3. Copious unit tests to make sure I didn't (AFAIK) break anything
during the refactoring portion of development.
4. Bonus: Scope model browser to only show in cloud distributions until
it's released elsewhere; should prevent some undesired UI behavior if a
user accidentally enables the assetAPI.

## Review Focus

Widget code: please double check the work there.

## Screenshots (if applicable)



https://github.com/user-attachments/assets/a94b3203-c87f-4285-b692-479996859a5a


┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-6585-Feat-input-mapping-2a26d73d365081faa667e49892c8d45a)
by [Unito](https://www.unito.io)

src/stores/assetsStore.ts

@@ -1,5 +1,6 @@
 import { useAsyncState } from '@vueuse/core'
 import { defineStore } from 'pinia'
+import { computed } from 'vue'
 
 import {
   mapInputFileToAssetItem,
@@ -12,6 +13,8 @@ import { api } from '@/scripts/api'
 
 import { TaskItemImpl } from './queueStore'
 
+const INPUT_LIMIT = 100
+
 /**
  * Fetch input files from the internal API (OSS version)
  */
@@ -36,7 +39,9 @@ async function fetchInputFilesFromAPI(): Promise<AssetItem[]> {
  * Fetch input files from cloud service
  */
 async function fetchInputFilesFromCloud(): Promise<AssetItem[]> {
-  return await assetService.getAssetsByTag('input', false)
+  return await assetService.getAssetsByTag('input', false, {
+    limit: INPUT_LIMIT
+  })
 }
 
 /**
@@ -117,6 +122,30 @@ export const useAssetsStore = defineStore('assets', () => {
     }
   })
 
+  /**
+   * Map of asset hash filename to asset item for O(1) lookup
+   * Cloud assets use asset_hash for the hash-based filename
+   */
+  const inputAssetsByFilename = computed(() => {
+    const map = new Map<string, AssetItem>()
+    for (const asset of inputAssets.value) {
+      // Use asset_hash as the key (hash-based filename)
+      if (asset.asset_hash) {
+        map.set(asset.asset_hash, asset)
+      }
+    }
+    return map
+  })
+
+  /**
+   * Get human-readable name for input asset filename
+   * @param filename Hash-based filename (e.g., "72e786ff...efb7.png")
+   * @returns Human-readable asset name or original filename if not found
+   */
+  function getInputName(filename: string): string {
+    return inputAssetsByFilename.value.get(filename)?.name ?? filename
+  }
+
   return {
     // States
     inputAssets,
@@ -128,6 +157,10 @@ export const useAssetsStore = defineStore('assets', () => {
 
     // Actions
     updateInputs,
-    updateHistory
+    updateHistory,
+
+    // Input mapping helpers
+    inputAssetsByFilename,
+    getInputName
   }
 })