feat: add Remotion video project + SquareMCP brand compositions

- Scaffold videos/remotion-demo with Remotion 4.0.459
- SquareMCPLinkedIn: 90s 1080×1080 LinkedIn explainer (6 scenes, spring animations)
- SquareMCPHeroLoop: 30s 1920×1080 seamless hero loop (node network + MCP layer + logo)
- Brand tokens from squaremcp-logo.svg (#0E63F6/#7DB6FF), Inter via @remotion/google-fonts
- Both compositions rendered to out/ and type-checked clean
- Update .gitignore to exclude videos/remotion-demo/node_modules and out/

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

videos/remotion-demo/public/squaremcp-logo.svg

@@ -0,0 +1,18 @@
+<svg width="64" height="64" viewBox="0 0 64 64" fill="none" xmlns="http://www.w3.org/2000/svg">
+  <title>SquareMCP logo</title>
+  <defs>
+    <linearGradient id="squaremcp-logo-gradient" x1="10" y1="10" x2="54" y2="54" gradientUnits="userSpaceOnUse">
+      <stop stop-color="#7DB6FF"/>
+      <stop offset="1" stop-color="#0E63F6"/>
+    </linearGradient>
+  </defs>
+  <path
+    d="M10 12C10 10.8954 10.8954 10 12 10H31V17H17V31H10V12ZM33 10H52C53.1046 10 54 10.8954 54 12V31H47V17H33V10ZM10 33H17V47H31V54H12C10.8954 54 10 53.1046 10 52V33ZM47 33H54V52C54 53.1046 53.1046 54 52 54H33V47H47V33Z"
+    fill="url(#squaremcp-logo-gradient)"
+  />
+  <path
+    d="M24 24H33V31H40V40H31V33H24V24Z"
+    fill="#0E63F6"
+    opacity="0.92"
+  />
+</svg>