refactor(video): single Foley-style upload loader with inline preview

Replace the path+dropdown loader (and its non-rendering ui.gifs) with one
node mirroring FoleyTuneVideoLoaderUpload: a `video` upload widget with
drag-drop and an inline video preview, shipped via web/js/UniverSRVideo.js
(adapted from FoleyTuneVideo.js) + WEB_DIRECTORY.

The loader now outputs (UNIVERSR_VIDEO, AUDIO) so you can super-resolve the
audio and remux it. Updated the example workflow output order and README.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

example_workflows/universr_video.json

@@ -12,11 +12,11 @@
       "mode": 0,
       "inputs": [],
       "outputs": [
-        {"name": "audio", "type": "AUDIO", "links": [1], "slot_index": 0},
-        {"name": "video", "type": "UNIVERSR_VIDEO", "links": [2], "slot_index": 1}
+        {"name": "video", "type": "UNIVERSR_VIDEO", "links": [2], "slot_index": 0},
+        {"name": "audio", "type": "AUDIO", "links": [1], "slot_index": 1}
       ],
       "properties": {"Node name for S&R": "UniverSRLoadVideoAudio"},
-      "widgets_values": ["/path/to/video.mp4", "(none)", 0.0, 0.0]
+      "widgets_values": ["video.mp4", 0.0, 0.0]
     },
     {
       "id": 2,
@@ -72,8 +72,8 @@
     }
   ],
   "links": [
-    [1, 1, 0, 3, 0, "AUDIO"],
-    [2, 1, 1, 4, 0, "UNIVERSR_VIDEO"],
+    [1, 1, 1, 3, 0, "AUDIO"],
+    [2, 1, 0, 4, 0, "UNIVERSR_VIDEO"],
     [3, 2, 0, 3, 1, "UNIVERSR_MODEL"],
     [4, 3, 0, 4, 1, "AUDIO"]
   ],