Performance Improvements & New Heatmap Mode

✨ Update - Heatmap toggle on the Globe - switch between User, Post, and Combined modes to see where Orbitail activity is concentrated around the world. - Refreshed post composer (Subject page) - cleaner layout and smoother flow when creating a post. ⚡ Performance - Globe code-splitting -the heavy 3D libraries now load only when needed, so the initial page is significantly lighter. - Smarter d3 imports - unused parts of the d3 library are no longer bundled, shrinking the JS payload. - Link prefetching - hovering over a navigation menu quietly preloads the next page, making transitions feel near-instant. - Removed redundant user lookups - fewer database calls on initial load. 🔍 Discoverability - Dynamic sitemap - every public post, hub, announcement, and feedback item is now automatically indexed by search engines. - robots.txt added - clearer signals to crawlers about which areas to index and which to skip. 🛠️ Other - Minor polish to the profile layout. Thanks for being part of Orbitail.