feat: liquid glass UI, blob background, redesign home/portfolio/about pages

- Liquid glass effect on navbar/cards with backdrop-filter invert
- Animated blob gradient background (SVG-based)
- Portfolio section: scene-dark invert, show 5 items on home
- How Work section: step flow with numbers + connecting lines
- Hero: Decision snapshot replacing problem selector
- About page: inverted background with contrast fixes
- Fix parallax JS bundling via Astro
- Fix navbar fixed positioning after liquid glass CSS
- Submenu hover fix
- Clean up removed legacy files/assets

astro.config.mjs

@@ -1,15 +1,8 @@
 // @ts-check
 import { defineConfig } from 'astro/config';
-import react from "@astrojs/react";
-import mdx from "@astrojs/mdx";
 
-// All content is markdown → static output. No server runtime needed.
 export default defineConfig({
-  output: "static",
-  integrations: [
-    react(),
-    mdx(),
-  ],
-  image: { layout: "constrained", responsiveStyles: true },
-  devToolbar: { enabled: true },
+  output: 'static',
+  image: { layout: 'constrained', responsiveStyles: true },
+  devToolbar: { enabled: false },
 });