[backport cloud/1.36] [feat] Add async model upload with WebSocket progress tracking (#7887)

Backport of #7746 to `cloud/1.36`

Automatically created by backport workflow.

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-7887-backport-cloud-1-36-feat-Add-async-model-upload-with-WebSocket-progress-tracking-2e26d73d365081c4a060e6e88f33016d)
by [Unito](https://www.unito.io)

Co-authored-by: Luke Mino-Altherr <luke@comfy.org>
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: GitHub Action <action@github.com>

tests-ui/tests/store/assetsStore.test.ts

@@ -15,6 +15,9 @@ vi.mock('@/scripts/api', () => ({
   api: {
     getHistory: vi.fn(),
     internalURL: vi.fn((path) => `http://localhost:3000${path}`),
+    apiURL: vi.fn((path) => `http://localhost:3000/api${path}`),
+    addEventListener: vi.fn(),
+    removeEventListener: vi.fn(),
     user: 'test-user'
   }
 }))