fix(frontend): finish the token migration — raw grey classes -> theme tokens

UI_REDESIGN chunk 4 was never finished: 39 app/component files still used
raw Tailwind greys, kept readable in light mode only by the !important
override sheet. In dark mode text-gray-600 is ~2.3:1 on surface, and the
light override maps it to #94a3b8 (~2.6:1 on white) — unreadable in both.

Mechanical mapping (886 classes): gray-100/200 -> ink, 300/400 -> ink-2,
500/600/700 -> ink-muted, bg 950/900/800 -> page/surface/raised,
border 800 -> line, 700/600 -> line-strong, plus hover/divide/placeholder.
Alpha suffixes kept (tokens are color-mix, so /60 works). bg-gray-700,
text-white and marketing pages left alone. text-[9px] -> text-[10px].

Frontend unverified: no Node on the authoring box (#207).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

drb-frontend/app/terms/page.tsx

@@ -69,18 +69,18 @@ export default function TermsPage() {
       </div>
 
       <h1 className="text-display-sm text-white">Terms of Service</h1>
-      <p className="text-gray-500 text-sm mt-2 font-mono">Draft — last structured {new Date().getFullYear()}</p>
+      <p className="text-ink-muted text-sm mt-2 font-mono">Draft — last structured {new Date().getFullYear()}</p>
 
       <div className="mt-10 space-y-8">
         {SECTIONS.map((s) => (
           <section key={s.heading}>
             <h2 className="text-white font-semibold">{s.heading}</h2>
-            <p className="text-gray-500 text-sm mt-2 leading-relaxed italic">{s.note}</p>
+            <p className="text-ink-muted text-sm mt-2 leading-relaxed italic">{s.note}</p>
           </section>
         ))}
       </div>
 
-      <p className="text-gray-600 text-xs font-mono mt-16">
+      <p className="text-ink-muted text-xs font-mono mt-16">
         Questions in the meantime? <Link href="/faq" className="text-indigo-400 hover:text-indigo-300 transition-colors">Check the FAQ</Link> or{" "}
         <Link href="/login" className="text-indigo-400 hover:text-indigo-300 transition-colors">sign in to reach us directly</Link>.
       </p>