fix: remove black border below video controls

- video: inline → block w-full (eliminates baseline descender gap)
- media-controller: fill parent container with absolute inset-0 w-full h-full

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

packages/frontend/src/routes/videos/[slug]/+page.svelte

@@ -162,14 +162,14 @@ let showPlayer = $state(false);
         >
           <div class="relative aspect-video bg-black">
             {#if showPlayer}
-              <media-controller>
+              <media-controller class="absolute inset-0 w-full h-full">
                 <video
                   slot="media"
                   src={getAssetUrl(data.video.movie)}
                   poster={getAssetUrl(data.video.image, 'preview')}
                   autoplay
                   ontimeupdate={handleTimeUpdate}
-                  class="inline"
+                  class="block w-full"
                 >
                   <track kind="captions" />
                 </video>