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

components/layout/vibn-sidebar.tsx

@@ -103,7 +103,7 @@ export function VIBNSidebar({ workspace, tabs, activeTab }: VIBNSidebarProps) {
       width: w, height: "100vh",
       background: "#fff", borderRight: "1px solid #e8e4dc",
       display: "flex", flexDirection: "column",
-      fontFamily: "Outfit, sans-serif",
+      fontFamily: "var(--font-inter), ui-sans-serif, sans-serif",
       flexShrink: 0, overflow: "hidden",
       transition, position: "relative",
     }}>
@@ -136,7 +136,7 @@ export function VIBNSidebar({ workspace, tabs, activeTab }: VIBNSidebarProps) {
             <div style={{ width: 26, height: 26, borderRadius: 7, overflow: "hidden", flexShrink: 0 }}>
               <img src="/vibn-black-circle-logo.png" alt="VIBN" style={{ width: "100%", height: "100%", objectFit: "cover" }} />
             </div>
-            <span style={{ fontSize: "0.92rem", fontWeight: 600, color: "#1a1a1a", letterSpacing: "-0.03em", fontFamily: "Newsreader, serif", whiteSpace: "nowrap" }}>
+            <span style={{ fontSize: "0.92rem", fontWeight: 600, color: "#1a1a1a", letterSpacing: "-0.03em", fontFamily: "var(--font-lora), ui-serif, serif", whiteSpace: "nowrap" }}>
               vibn
             </span>
           </Link>
@@ -334,7 +334,7 @@ export function VIBNSidebar({ workspace, tabs, activeTab }: VIBNSidebarProps) {
             <button onClick={() => signOut({ callbackUrl: "/auth" })} style={{
               background: "none", border: "none", padding: 0,
               fontSize: "0.62rem", color: "#a09a90", cursor: "pointer",
-              fontFamily: "Outfit, sans-serif",
+              fontFamily: "var(--font-inter), ui-sans-serif, sans-serif",
             }}>
               Sign out
             </button>