Fix: update arc section header from 64 to 69 questions in Landing.jsx

The hero text was updated in the previous commit but the phases preview
section heading on the same page still said "The 64-Question Arc."

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: Jamie Nucho

web/src/components/Landing.jsx

@@ -83,7 +83,7 @@ export default function Landing({ data }) {
       {/* Phases preview */}
       <section className="border-t border-border">
         <div className="max-w-5xl mx-auto px-4 py-12">
-          <p className="text-xs text-muted tracking-wider uppercase mb-6">The 64-Question Arc</p>
+          <p className="text-xs text-muted tracking-wider uppercase mb-6">The 69-Question Arc</p>
           <div className="grid gap-3">
             {data.phases.map(phase => {
               const phaseQs = questions.filter(q => q.phase === phase.id)