Wave 4B: Parlay Lab page + Live Grade-Shift timeline

TASK 1 — Parlay Lab (/parlay): a dedicated Correlation Builder with a
leg source INDEPENDENT of the live slate. Browses tonight's pre-graded
props from /api/snapshot/:sport (resolves players via /api/players/search),
adds legs through useParlay().addLeg (deduped by legKey), and renders the
PARLAY SLIP — combined grade, correlation, and payout read straight off
ParlayContext. Surfaces parlayService's correlation warning as the
CAUTION · CORRELATION FLAG, honors the tier leg-cap (free 2 / analyst 4 /
desk 6) and blurs the payout for free tier with the __goPaywall upsell.
Added /parlay to OPEN_ROUTES (free funnel, like scan/dashboard). Retired
the cleanly-dead ParlayTray.tsx (unmounted since Session 50). No new
proxies — reuses existing snapshot/search/parlay-grade endpoints.

TASK 2 — Live Grade-Shift timeline: web/src/lib/gradeShift.js (pure,
testable) builds a line/grade-movement timeline from already-emitted data
(intraday {t,line} history + revised_from_grade). Color law mirrors
ROW-GRAMMAR / StatStrip.LineSparkline: green = toward the graded side,
amber = against, dim = flat (never red). GradeShift.tsx renders it, shows
the original grade struck-through on a revision, and self-hides below 3
real points. Mounted in GradeResultCard (self-hides on the scan path,
which carries no captured history — honest, never fabricated).

Tests: tests/unit/gradeShift.test.js (15) + tests/unit/parlayLab.test.js
(13). Full suite 245 suites / 2989 tests green (baseline 243/2961).
Next build EXIT=0.

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

web/src/lib/gradeShift.js

@@ -0,0 +1,94 @@
+/* ============================================================
+   VYNDR — LIVE GRADE-SHIFT timeline helper (Wave 4B).
+   Pure CommonJS so the client component imports it (allowJs)
+   AND the Jest suite requires it directly.
+
+   Builds a grade/line-movement timeline from ALREADY-EMITTED data
+   (intradayRefreshService line history {t,line} + revised_from_grade).
+   It NEVER fabricates: absent/short history => { show:false }.
+
+   COLOR LAW (mirrors ROW-GRAMMAR + StatStrip.LineSparkline):
+   line movement is green = net move TOWARD the graded side,
+   amber = AGAINST, dim = flat. Never red — nothing here is settled.
+   For an OVER the "toward" sign is the raw line delta; for an UNDER
+   it is inverted (a line dropping steams the under).
+   ============================================================ */
+
+const TOWARD_COLOR = 'var(--g-a)'; // green
+const AGAINST_COLOR = 'var(--amber)'; // amber
+const FLAT_COLOR = 'var(--text-1)'; // dim — never red
+const MIN_POINTS = 3; // self-hide below this (same floor as LineSparkline)
+
+function isUnder(side) {
+  return String(side || 'O').toUpperCase().startsWith('U');
+}
+
+/** Classify a signed line delta relative to the graded side. */
+function classifyMove(delta, side) {
+  const d = typeof delta === 'number' && Number.isFinite(delta) ? delta : 0;
+  const toward = isUnder(side) ? -d : d;
+  if (toward > 0) return { dir: 'toward', color: TOWARD_COLOR };
+  if (toward < 0) return { dir: 'against', color: AGAINST_COLOR };
+  return { dir: 'flat', color: FLAT_COLOR };
+}
+
+/** Keep only real {t, line} points (strict number guard — Number(null)===0). */
+function cleanHistory(history) {
+  if (!Array.isArray(history)) return [];
+  return history
+    .filter((pt) => pt && typeof pt.line === 'number' && Number.isFinite(pt.line))
+    .map((pt) => ({ t: pt.t != null ? String(pt.t) : '', line: pt.line }));
+}
+
+/**
+ * Build the grade-shift timeline.
+ * prop: { history:[{t,line}], side, grade, revisedFrom|revised_from_grade, gradedLine }
+ * -> { show, points:[{t,line,delta,dir,color}], net:{delta,dir,color},
+ *      revision:{from,to}|null, firstLine, lastLine }
+ */
+function buildGradeTimeline(prop = {}) {
+  const history = cleanHistory(prop.history);
+  const show = history.length >= MIN_POINTS;
+  const side = prop.side;
+  const revisedFrom = prop.revisedFrom || prop.revised_from_grade || null;
+  const grade = prop.grade || null;
+
+  const points = history.map((pt, i) => {
+    if (i === 0) return { t: pt.t, line: pt.line, delta: 0, dir: 'flat', color: FLAT_COLOR };
+    const delta = Math.round((pt.line - history[i - 1].line) * 100) / 100;
+    const cls = classifyMove(delta, side);
+    return { t: pt.t, line: pt.line, delta, dir: cls.dir, color: cls.color };
+  });
+
+  let net = { delta: 0, dir: 'flat', color: FLAT_COLOR };
+  if (history.length >= 2) {
+    const raw = Math.round((history[history.length - 1].line - history[0].line) * 100) / 100;
+    const cls = classifyMove(raw, side);
+    net = { delta: raw, dir: cls.dir, color: cls.color };
+  }
+
+  // A revision is real only when a prior grade was preserved AND it differs.
+  const revision = revisedFrom && grade && String(revisedFrom) !== String(grade)
+    ? { from: String(revisedFrom), to: String(grade) }
+    : null;
+
+  return {
+    show,
+    points,
+    net,
+    revision,
+    firstLine: history.length ? history[0].line : null,
+    lastLine: history.length ? history[history.length - 1].line : null,
+  };
+}
+
+module.exports = {
+  buildGradeTimeline,
+  classifyMove,
+  cleanHistory,
+  isUnder,
+  TOWARD_COLOR,
+  AGAINST_COLOR,
+  FLAT_COLOR,
+  MIN_POINTS,
+};

web/src/lib/routes.js

@@ -35,6 +35,10 @@ const OPEN_ROUTES = [
   '/dashboard',
   '/slate',
   '/scan',
+  /* Wave 4B — the Parlay Lab is the parlay-building funnel: anon/free reach it
+     (free 2-leg cap + payout-blur upsell), same monetization logic as scan +
+     dashboard, so it stays OPEN, not gated. */
+  '/parlay',
   '/compare',
   '/game',
   '/pricing',