Item 6 — Desk showcase renders REAL data (or hides), kills the mocked ladder

The pricing Desk showcase hardcoded an alt-line ladder (1.5 A +7.1% / 2.5 A+
+11.4% / 4.5 C -3.8%), QUARTER-KELLY 2.4%, and PARLAY φ 0.34 — a mocked demo
selling something we weren't proving.

- deskShowcaseService reads the pre-graded snapshot for a real A/B prop's
  alt-line ladder (prefers the one with the most grade variation — the most
  compelling real example). Edge per rung shows only when it's a plausible
  market value; the inflated (model-line)/line artifact on small lines is
  guarded to "—" rather than shown as a fake +91%.
- PARLAY φ is now REAL: the model's same-team correlation (0.34, mirroring the
  frontend parlayMath team constant) computed for TWO REAL same-team legs,
  named. No real same-team pair on the board → the tile hides, never an
  invented number.
- QUARTER-KELLY tile is REMOVED: the snapshot has no odds, so a real
  quarter-Kelly % can't be computed here — a fabricated 2.4% is worse than
  nothing. Kelly stays a real in-app Desk feature; the showcase just doesn't
  fake it.
- DeskShowcase is now a client component fetching /api/desk-showcase; when the
  board has no real ladder the whole visuals column hides (real-or-hidden, same
  law as the hero). The pitch copy is unchanged.

5 service tests. Change-affected suites green, web build exit 0.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

web/src/app/api/desk-showcase/route.ts

@@ -0,0 +1,21 @@
+import { NextResponse } from 'next/server';
+
+export const dynamic = 'force-dynamic';
+
+const BACKEND_URL = process.env.BACKEND_URL || 'http://localhost:3000';
+
+/**
+ * Desk-showcase proxy (item 6) — real alt-line ladder + same-team correlation
+ * from the snapshot. Any failure → { available:false } so the visuals hide.
+ */
+export async function GET() {
+  try {
+    const upstream = await fetch(`${BACKEND_URL}/api/desk-showcase`, {
+      method: 'GET', headers: { Accept: 'application/json' }, cache: 'no-store',
+    });
+    const data = await upstream.json().catch(() => ({ available: false }));
+    return NextResponse.json(data, { status: 200, headers: { 'Cache-Control': 'public, s-maxage=300, stale-while-revalidate=60' } });
+  } catch {
+    return NextResponse.json({ available: false }, { status: 200 });
+  }
+}