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/src/Root.tsx

@@ -0,0 +1,27 @@
+import "./index.css";
+import { Composition } from "remotion";
+import { SquareMCPLinkedIn } from "./SquareMCPLinkedIn";
+import { SquareMCPHeroLoop } from "./SquareMCPHeroLoop";
+
+export const RemotionRoot = () => {
+  return (
+    <>
+      <Composition
+        id="SquareMCPLinkedIn"
+        component={SquareMCPLinkedIn}
+        durationInFrames={90 * 30}
+        fps={30}
+        width={1080}
+        height={1080}
+      />
+      <Composition
+        id="SquareMCPHeroLoop"
+        component={SquareMCPHeroLoop}
+        durationInFrames={30 * 30}
+        fps={30}
+        width={1920}
+        height={1080}
+      />
+    </>
+  );
+};