Add arcade launch video to landing page

assets/arcade_launch.mp4

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:b3e2448d629b4361c7957e24116484ec7f78492335141d22f20f426e24405b3a
+size 32829818

index.html

@@ -73,9 +73,9 @@
         </div>
 
         <div>
-          <div class="placeholder-image">
-            Screenshot coming soon
-          </div>
+          <video class="demo-video" autoplay loop muted playsinline>
+            <source src="assets/arcade_launch.mp4" type="video/mp4">
+          </video>
         </div>
       </div>
     </div>