Item 5 — daily hero prop is a live RULE (biggest model-vs-market disagreement)

The landing hero was a static Jokic "Example" card with a name-length pick and a
hardcoded A- 73% +6.2% fallback. Now it's deterministic and live:

- heroPropService.pickHeroProp reads the pre-graded snapshot and selects the
  prop with the LARGEST |projection - line| gap among A/B grades (conviction,
  not noise) — the read where VYNDR disagrees most with the market, the card
  that makes a stranger argue. No curation, no grading (reads cache → no API
  credits). GET /api/hero-prop (backend) + repointed Next proxy.
- The card shows the disagreement EXPLICITLY: the book's line vs VYNDR's model,
  side by side (model in green), with the real grade timestamp ("Graded 2:14
  PM"). The EXAMPLE chip is gone.
- Empty slate → the MOST RECENT real graded read (flagged "LATEST READ", real
  date). Nothing cached → { available:false } and the card HIDES. No
  hand-written fallback — the Jokic card is deleted. Survives a dead night: a
  live rule shows tonight's real MLB read, never a phantom July NBA card.

7 service tests lock the rule (max-gap, A/B gate, projection/line required,
empty→recent, hidden, cross-sport). colorContract updated to the new
disagreement display. Change-affected suites green, web build exit 0.

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

src/routes/heroProp.js

@@ -0,0 +1,29 @@
+'use strict';
+
+/**
+ * GET /api/hero-prop (Truth-Everywhere Part 2, item 5) — the daily hero prop:
+ * the live read where VYNDR disagrees most with the market (largest
+ * |model - consensus| gap, A/B only). Public, cache-only (reads the pre-graded
+ * snapshot) → never triggers grading, never spends API credits. Empty slate →
+ * most recent real graded read; nothing cached → { available:false } (hides).
+ */
+
+const express = require('express');
+const { createRateLimit } = require('../middleware/rateLimit');
+const heroPropService = require('../services/heroPropService');
+
+const router = express.Router();
+router.use(createRateLimit({ windowMs: 60_000, max: 60 }));
+
+router.get('/', async (req, res) => {
+  try {
+    const hero = await heroPropService.pickHeroProp({});
+    res.set('Cache-Control', 'public, max-age=300');
+    return res.json(hero);
+  } catch (err) {
+    console.error('[hero-prop]', err.message);
+    return res.status(200).json({ available: false });
+  }
+});
+
+module.exports = router;