feat: social video uploads + hero page video + TikTok content

Hero page:
- Replace GIF with squaremcp-hero-loop.mp4 (autoplay, muted, loop)
- Update styles, scripts, tests, Dockerfile, baselines
- Deployed and verified

Social video uploads:
- Twitter/X: uploadVideoAndTweet via v1.1 media/upload + v2 tweets
- Facebook: createVideoPost via Graph API /{pageId}/videos
- Instagram: createReel via Graph API (container → poll → publish)
- TikTok: REST endpoints + OpenAPI schema for video upload

Marketing:
- TikTok content prompts, scripts, and posting schedule

Note: Remotion not mentioned in any user-facing content

product/site/server.mjs

@@ -14,6 +14,7 @@ const contentTypes = {
   ".css": "text/css; charset=utf-8",
   ".js": "text/javascript; charset=utf-8",
   ".json": "application/json; charset=utf-8",
+  ".mp4": "video/mp4",
 };
 
 function resolvePath(urlPath) {