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

app/(marketing)/layout.tsx

@@ -38,7 +38,7 @@ export default function MarketingLayout({
                 alt="Vib'n" 
                 className="h-8 w-8"
               />
-              <span className="text-xl font-bold">Vib&apos;n</span>
+              <span className="font-serif text-xl font-bold tracking-tight">Vib&apos;n</span>
             </Link>
           </div>
           <div className="flex flex-1 items-center justify-between space-x-2 md:justify-end">