radiance: new home page — WebGL orb hero, DG cube loader, white dropdown menu

Replaces the Crush landing page with a single-screen hero (no scroll):
gradient sky, particle orb with corona, 'Welcome to dangrubb.net' title,
top-left DG logo and a numbered menu. Raw WebGL (no three.js), self-hosted
Instrument Sans + Geist Mono. ~10 KB of JS.

package-lock.json

@@ -8,6 +8,8 @@
       "name": "dangrubb-astro",
       "version": "0.0.1",
       "dependencies": {
+        "@fontsource/geist-mono": "^5.3.0",
+        "@fontsource/instrument-sans": "^5.3.0",
         "astro": "^6.1.9"
       },
       "engines": {
@@ -593,6 +595,24 @@
         "node": ">=18"
       }
     },
+    "node_modules/@fontsource/geist-mono": {
+      "version": "5.3.0",
+      "resolved": "https://registry.npmjs.org/@fontsource/geist-mono/-/geist-mono-5.3.0.tgz",
+      "integrity": "sha512-UtJ1BBBCVpMYdIcW7nEB45UAoAw5M53ZXs2t0ciPW+IokuAAIc56M8+kW5tXbRJCTpDw4XTtU7proT6NdQAHTg==",
+      "license": "OFL-1.1",
+      "funding": {
+        "url": "https://github.com/sponsors/ayuhito"
+      }
+    },
+    "node_modules/@fontsource/instrument-sans": {
+      "version": "5.3.0",
+      "resolved": "https://registry.npmjs.org/@fontsource/instrument-sans/-/instrument-sans-5.3.0.tgz",
+      "integrity": "sha512-QwXc4hb/px3XvSPS2CPAOgey8nyrQFxgxrmXQQ+pN+P51hKdAcchxpg8rSbjANFfPu6VKXhDqkVDucXMZ9CM5g==",
+      "license": "OFL-1.1",
+      "funding": {
+        "url": "https://github.com/sponsors/ayuhito"
+      }
+    },
     "node_modules/@img/colour": {
       "version": "1.1.0",
       "resolved": "https://registry.npmjs.org/@img/colour/-/colour-1.1.0.tgz",