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/[workspace]/activity/page.tsx

@@ -58,10 +58,10 @@ export default function ActivityPage() {
   return (
     <div
       className="vibn-enter"
-      style={{ padding: "44px 52px", maxWidth: 720, fontFamily: "Outfit, sans-serif" }}
+      style={{ padding: "44px 52px", maxWidth: 720, fontFamily: "var(--font-inter), ui-sans-serif, sans-serif" }}
     >
       <h1 style={{
-        fontFamily: "Newsreader, serif", fontSize: "1.9rem",
+        fontFamily: "var(--font-lora), ui-serif, serif", fontSize: "1.9rem",
         fontWeight: 400, color: "#1a1a1a", letterSpacing: "-0.03em", marginBottom: 4,
       }}>
         Activity
@@ -81,7 +81,7 @@ export default function ActivityPage() {
               background: filter === f.id ? "#1a1a1a" : "#fff",
               color: filter === f.id ? "#fff" : "#6b6560",
               fontSize: "0.75rem", fontWeight: 600, transition: "all 0.12s",
-              cursor: "pointer", fontFamily: "Outfit, sans-serif",
+              cursor: "pointer", fontFamily: "var(--font-inter), ui-sans-serif, sans-serif",
             }}
           >
             {f.label}