Add scan-to-join QR code under the hero CTA

Self-hosted SVG QR (CSP-safe) pointing at /start?utm_source=qr, so
scanned visits appear as their own "qr" source row in admin analytics.
Sits between the CTA and "See the Strategy" on mobile for the
show-your-phone recruiting flow; centered below the buttons on desktop.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

public/styles.css

@@ -106,3 +106,11 @@ a{color:inherit}.wrap{width:min(1160px,calc(100% - 32px));margin:auto}.nav{heigh
 .q-no{background:rgba(174,189,202,.08);color:var(--muted);border:1px solid #33506a}
 .mtp-card{position:relative}
 .mtp-qmark{position:absolute;top:-8px;right:-8px;width:20px;height:20px;border-radius:50%;background:linear-gradient(135deg,var(--gold),#f7d173);color:#152033;font-size:12px;font-weight:900;display:grid;place-items:center;box-shadow:0 2px 8px rgba(0,0,0,.4)}
+
+/* Hero QR — between the buttons on mobile (show-your-phone flow), tucked after them on desktop */
+.qr-cta{display:flex;align-items:center;gap:12px;text-align:left}
+.qr-cta img{background:#fff;padding:7px;border-radius:12px;display:block;box-shadow:0 8px 24px rgba(0,0,0,.3)}
+.qr-cta span{font-size:13px;font-weight:800;line-height:1.45}
+.qr-cta small{color:var(--muted);font-weight:600}
+@media(min-width:561px){.hero-actions{align-items:center}.qr-cta{order:3;flex-basis:100%;justify-content:center;margin-top:8px}}
+@media(max-width:560px){.qr-cta{justify-content:center}}