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)

tests-ui/tests/services/assetService.test.ts

@@ -376,5 +376,48 @@ describe('assetService', () => {
       )
       expect(result).toEqual(testAssets)
     })
+
+    it('should accept custom limit via options', async () => {
+      const testAssets = [MOCK_ASSETS.checkpoints]
+      mockApiResponse(testAssets)
+
+      const result = await assetService.getAssetsByTag('input', false, {
+        limit: 100
+      })
+
+      expect(api.fetchApi).toHaveBeenCalledWith(
+        '/assets?include_tags=input&limit=100&include_public=false'
+      )
+      expect(result).toEqual(testAssets)
+    })
+
+    it('should accept custom offset via options', async () => {
+      const testAssets = [MOCK_ASSETS.loras]
+      mockApiResponse(testAssets)
+
+      const result = await assetService.getAssetsByTag('models', true, {
+        offset: 50
+      })
+
+      expect(api.fetchApi).toHaveBeenCalledWith(
+        '/assets?include_tags=models&limit=500&include_public=true&offset=50'
+      )
+      expect(result).toEqual(testAssets)
+    })
+
+    it('should accept both limit and offset via options', async () => {
+      const testAssets = [MOCK_ASSETS.checkpoints]
+      mockApiResponse(testAssets)
+
+      const result = await assetService.getAssetsByTag('input', false, {
+        limit: 100,
+        offset: 25
+      })
+
+      expect(api.fetchApi).toHaveBeenCalledWith(
+        '/assets?include_tags=input&limit=100&include_public=false&offset=25'
+      )
+      expect(result).toEqual(testAssets)
+    })
   })
 })