Rework website palette, copy, and theme support

- Align color palette with TUI Everforest theme (feynman.json)
- Rewrite homepage copy with sharper section headings and descriptions
- Fix dark/light theme toggle persistence across page navigation
- Add Shiki Everforest syntax themes for code blocks
- Fix copy-code button z-index and pointer events
- Add styled scrollbars and text selection colors
- Tighten hero image padding, remove unused public/hero.png
- Remove Modal/RunPod from site (Docker only for now)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

website/src/layouts/Base.astro

@@ -37,8 +37,11 @@ const { title, description = 'Research-first AI agent', active = 'home' } = Astr
     document.addEventListener('astro:after-swap', function() {
       var stored = localStorage.getItem('theme');
       var prefersDark = window.matchMedia('(prefers-color-scheme: dark)').matches;
-      if (stored === 'dark' || (!stored && prefersDark)) {
+      var shouldBeDark = stored === 'dark' || (!stored && prefersDark);
+      if (shouldBeDark) {
         document.documentElement.classList.add('dark');
+      } else {
+        document.documentElement.classList.remove('dark');
       }
       var isDark = document.documentElement.classList.contains('dark');
       var sun = document.getElementById('sun-icon');