Model Train arc 1 (engine): de-vig + EV + takeable/value gates + hero v2 + triplet

Steps 1-6 — make "real opportunities at takeable prices" the engine, not a filter.

1. DE-VIG (src/utils/devig.js): two-way multiplicative de-vig strips the vig and
   returns fair prob + fair price per side + the overround. One side missing →
   fair UNAVAILABLE (null), never faked. Method noted in code + the `devig_method`
   field.
2. EV (devig.evPct): ev_pct = model prob × decimal − 1 at the graded side's
   ACTUAL price. This is the ranking signal now, replacing raw |model−consensus|.
3. TAKEABLE gate (src/config/valueEngine.js, TAKEABLE_ODDS_CEILING −160 .. +200,
   env-tunable): promoted surfaces only (hero/featured/alerts). The full board
   still shows everything; Parlay Lab exempt; JUICE_ODDS_FLOOR (−400) stays the
   absolute backstop underneath. Strict null-guard (Number(null)===0 would have
   made a missing price "takeable").
4. VALUE flag: passes BOTH gates (takeable AND ev_pct ≥ VALUE_EV_THRESHOLD).
   Grade = read quality; value = the price pays you. Shipped in payloads.
5. HERO v2 (heroPropService): highest ev_pct among takeable A/B reads — a huge
   gap on a −900 line is trivia, not an opportunity.
6. VALUE TRIPLET: book_odds · fair_odds · model_odds on every read (snapshot,
   hero, scan — they all spread the grade). Handoff documents the fields; the
   rendering is Session-2 Design's job.

All wired in analyzeViaEngine1's existing p_win/kelly block (real quantile
probability × real book odds, or nothing). 33 new tests; suite 276/3306 green.

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

tests/unit/valueEngine.test.js

@@ -0,0 +1,83 @@
+'use strict';
+
+// Model Train — value engine: takeable gate, value flag, and the end-to-end
+// wiring in analyzeViaEngine1 (de-vig + EV + triplet + flags).
+
+const ve = require('../../src/config/valueEngine');
+
+describe('valueEngine config (steps 3-4)', () => {
+  test('takeable band is -160..+200 by default', () => {
+    expect(ve.isTakeable(-110)).toBe(true);
+    expect(ve.isTakeable(-160)).toBe(true);   // ceiling inclusive
+    expect(ve.isTakeable(+200)).toBe(true);   // max inclusive
+    expect(ve.isTakeable(-200)).toBe(false);  // too chalky
+    expect(ve.isTakeable(+250)).toBe(false);  // too long
+    expect(ve.isTakeable(null)).toBe(false);
+  });
+  test('value = takeable AND ev above threshold', () => {
+    expect(ve.isValue(-120, 5)).toBe(true);   // takeable + 5% EV
+    expect(ve.isValue(-120, 1)).toBe(false);  // takeable but EV below 2%
+    expect(ve.isValue(-900, 20)).toBe(false); // huge EV but not takeable
+  });
+});
+
+// ── analyzeViaEngine1 value fields ──────────────────────────────────────────
+const mockCompute = { current: null };
+jest.mock('../../src/services/intelligence/computeFeatures', () => ({
+  computeFeaturesForProp: async () => mockCompute.current,
+}));
+jest.mock('../../src/services/intelligence/engine1', () => ({
+  gradeProp: () => ({ grade: 'B', confidence: 0.55, top_factors: [], all_factors: [] }),
+}));
+const mockPOver = { current: 0.6 };
+jest.mock('../../src/services/intelligence/probabilityEstimator', () => ({
+  estimateProbability: () => ({ p_over: mockPOver.current }),
+}));
+const { analyzeViaEngine1 } = require('../../src/services/intelligence/analyzeViaEngine1');
+
+beforeEach(() => {
+  mockCompute.current = {
+    features: { l5_avg: 1.4, l20_avg: 1.3 }, trap: {}, consistency: { consistency: 'reliable', score: 0.7 },
+    prop: { line: 0.5, direction: 'over' }, meta: { sport: 'mlb', gameLogs: [{ hits: 1 }], errors: [] },
+  };
+  mockPOver.current = 0.6; // model P(over) = 60%
+});
+
+describe('analyzeViaEngine1 — de-vig + EV + triplet (steps 1,2,6)', () => {
+  test('computes the value triplet, EV, and flags from both-sided odds', async () => {
+    // book: over -130 / under +110. model P(over) 0.60.
+    const out = await analyzeViaEngine1({
+      player: 'X', stat_type: 'hits', line: 0.5, direction: 'over', over_odds: -130, under_odds: 110,
+    });
+    expect(out.grade).toBe('B');            // still a real read
+    expect(out.book_odds).toBe(-130);       // book price
+    expect(typeof out.fair_odds).toBe('number'); // de-vigged fair price present (both sides)
+    expect(out.model_odds).toBe(-150);      // impliedProbToAmerican(0.60)
+    expect(out.p_win).toBe(0.6);
+    // EV at -130 with p 0.60: 0.60*(1+100/130) - 1 = +6.15%
+    expect(out.ev_pct).toBeGreaterThan(5);
+    expect(out.takeable).toBe(true);        // -130 in band
+    expect(out.value).toBe(true);           // takeable + EV > 2%
+    expect(out.devig_method).toBe('multiplicative');
+  });
+
+  test('one-sided odds → fair UNAVAILABLE, but book price + EV still ship', async () => {
+    const out = await analyzeViaEngine1({
+      player: 'X', stat_type: 'hits', line: 0.5, direction: 'over', over_odds: -130, // no under_odds
+    });
+    expect(out.book_odds).toBe(-130);
+    expect(out.fair_odds).toBeUndefined();  // never faked from one side
+    expect(out.ev_pct).toBeGreaterThan(0);  // EV from model + actual price
+    expect(out.takeable).toBe(true);
+  });
+
+  test('a chalky price is not takeable → not value even at positive EV', async () => {
+    mockPOver.current = 0.92;
+    const out = await analyzeViaEngine1({
+      player: 'X', stat_type: 'hits', line: 0.5, direction: 'over', over_odds: -600, under_odds: 400,
+    });
+    // -600 is past the JUICE_ODDS_FLOOR (-400) → refused before we even get here
+    expect(out.grade).toBeNull();
+    expect(out.suppressed_reason).toBe('juiced_no_edge');
+  });
+});