feat: add dark theme support and update homepage content

- Integrated next-themes for dark mode theming with default dark theme
- Added new UI components (GridBlink, Spotlight) and enhanced world map with cyan glow effects
- Updated homepage messaging to emphasize Mycelium as a living network with new audience imagery

src/main.tsx

@@ -1,10 +1,13 @@
 import { StrictMode } from 'react'
 import { createRoot } from 'react-dom/client'
+import { ThemeProvider } from 'next-themes'
 import './styles/tailwind.css'
 import App from './App'
 
 createRoot(document.getElementById('root')!).render(
   <StrictMode>
-    <App />
+    <ThemeProvider attribute="class" defaultTheme="dark" enableSystem>
+      <App />
+    </ThemeProvider>
   </StrictMode>,
 )