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

package.json

@@ -30,6 +30,7 @@
     "framer-motion": "^10.18.0",
     "lucide-react": "^0.544.0",
     "motion": "^12.23.24",
+    "next-themes": "^0.4.6",
     "popmotion": "^11.0.5",
     "react": "^18.3.1",
     "react-countup": "^6.5.3",