feat: scaffold Astro project with layout, nav, hero and concept sections

- Add global ocean-themed styles (Inter + Sora, glassmorphism utilities).
- Wire up base layout, sticky nav and footer respecting base path.
- Build hero with stylised rock SVG + sonar ambient rings and concept pipeline schematic.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

public/favicon.svg

@@ -0,0 +1,14 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 64 64">
+  <defs>
+    <linearGradient id="g" x1="0" x2="0" y1="0" y2="1">
+      <stop offset="0" stop-color="#38bdf8"/>
+      <stop offset="1" stop-color="#06b6d4"/>
+    </linearGradient>
+  </defs>
+  <rect width="64" height="64" rx="14" fill="#050d1a"/>
+  <path d="M6 40c6 0 6-6 12-6s6 6 12 6 6-6 12-6 6 6 12 6 6-6 10-6v14H6z" fill="url(#g)" opacity="0.55"/>
+  <path d="M6 46c6 0 6-6 12-6s6 6 12 6 6-6 12-6 6 6 12 6 6-6 10-6v8H6z" fill="url(#g)"/>
+  <circle cx="32" cy="22" r="4" fill="#e0f2fe"/>
+  <circle cx="32" cy="22" r="9" fill="none" stroke="#38bdf8" stroke-width="1.5" opacity="0.6"/>
+  <circle cx="32" cy="22" r="14" fill="none" stroke="#38bdf8" stroke-width="1" opacity="0.3"/>
+</svg>