feat(ui): apply Justine ink & parchment design system

- Map Justine tokens to shadcn CSS variables (--vibn-* aliases)
- Switch fonts to Inter + Lora via next/font (IBM Plex Mono for code)
- Base typography: body Inter, h1–h3 Lora; marketing hero + wordmark serif
- Project shell and global chrome use semantic colors
- Replace Outfit/Newsreader references across TSX inline styles

Made-with: Cursor

marketing/components/hero.tsx

@@ -10,7 +10,7 @@ export function Hero() {
         <div className="flex flex-col items-center gap-6 pb-16 pt-16 md:py-24 lg:py-32">
           <div className="flex max-w-[980px] flex-col items-center gap-6 text-center">
         {/* Main title */}
-        <h1 className="text-3xl font-extrabold leading-tight tracking-tighter md:text-5xl lg:text-6xl lg:leading-[1.1]">
+        <h1 className="font-serif text-3xl font-bold leading-tight tracking-tight md:text-5xl md:font-semibold lg:text-6xl lg:leading-[1.1]">
           {homepage.hero.title}
         </h1>