feat(video-layout): make videos fill tiles and remove blurred background

Videos now use object-fit: cover in all thumbnail types, removing dark
bars around portrait videos. Hides the blurred large video background
and makes the large video fill its container edge-to-edge.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

css/_videolayout_default.scss

@@ -25,20 +25,7 @@
 
 #largeVideoBackgroundContainer,
 .large-video-background {
-    height: 100%;
+    display: none;
-    left: 0;
-    overflow: hidden;
-    position: absolute;
-    top: 0;
-    width: 100%;
-
-    #largeVideoBackground {
-        min-height: 100%;
-        min-width: 100%;
-    }
-}
-#largeVideoBackgroundContainer {
-    filter: blur(40px);
 }
 
 .videocontainer {
@@ -122,6 +109,14 @@
 #largeVideoWrapper
 {
     object-fit: cover;
+    width: 100% !important;
+    height: 100% !important;
+    top: 0 !important;
+    left: 0 !important;
+}
+
+#largeVideo {
+    object-fit: cover;
 }
 
 #sharedVideo video {

react/features/filmstrip/components/web/Thumbnail.tsx

@@ -665,19 +665,12 @@ class Thumbnail extends Component<IProps, IState> {
             _isHidden,
             _isScreenSharing,
             _participant,
-            _thumbnailType,
             _videoObjectPosition,
-            _videoTrack,
             _width,
             horizontalOffset,
             style
         } = this.props;
 
-        const isTileType = _thumbnailType === THUMBNAIL_TYPE.TILE;
-        const jitsiVideoTrack = _videoTrack?.jitsiTrack;
-        const track = jitsiVideoTrack?.track;
-        const isPortraitVideo = (track?.getSettings()?.aspectRatio || 1) < 1;
-
         let styles: {
             avatar: Object;
             thumbnail: any;
@@ -696,8 +689,7 @@ class Thumbnail extends Component<IProps, IState> {
         }
 
         let videoStyles: any = null;
-        const doNotStretchVideo = (isPortraitVideo && isTileType)
+        const doNotStretchVideo = _disableTileEnlargement
-            || _disableTileEnlargement
             || _isScreenSharing;
 
         if (canPlayEventReceived || _participant.local || _isVirtualScreenshareParticipant) {