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>

.gitignore

@@ -0,0 +1,10 @@
+node_modules/
+dist/
+.astro/
+.DS_Store
+*.log
+.env
+.env.local
+.env.*.local
+.vscode/
+.idea/