Suppress rare-event 0.5 unders (juiced, no-edge) — config-driven grade + board fix

Betting-logic audit: the CONSENSUS-vs-MODEL board flooded with fake reads like
"DOUBLES u0.5 · MODEL 0.2 · +edge" — the juiced under side of rare counting-stat
markets (doubles/triples/HR/SB), which is never a takeable edge and violates the
no-unders-default doctrine.

Report finding (item 3/4): the doubles projection is REAL per-player, not a flat
fallback — 'doubles' maps to a real game-log field (MLB_LOG_FIELD doubles→
doubles) and the live values varied (0.03/0.16/0.2/0.22). So no projection-gate
refusal for fakeness; the problem is purely structural (a rare event's real
projection always sits below a 0.5 line, so the under always "wins").

Fix (config-driven — src/config/rareEventMarkets.js, tunable stat list + line
threshold):
- Grade layer (analyzeViaEngine1): a rare-event UNDER at ≤0.5 is always REFUSED
  (grade null + suppressed flag/reason). A rare-event OVER at ≤0.5 is refused
  UNLESS the model genuinely projects the event above the line — because a
  0.2-over-0.5 carries the SAME |edge| as the suppressed under and would just
  take its rank on the board. The over grades normally once projection > line.
- Board layer (marketBreadth.collectBreadth): drops null-model rows so a
  suppressed/ungraded prop can't rank a "MODEL —" placeholder onto the board.

10 suppression tests + config locks; also fixed a settingsPage book assertion
left over from the ESPN→theScore swap. Suite 274/3289 green, web build exit 0.

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

tests/unit/settingsPage.test.js

@@ -10,7 +10,8 @@ describe('books lib (BookChip data)', () => {
   it('maps known books to brand colors (case-insensitive aliases)', () => {
     expect(bookInfo('DK')).toMatchObject({ name: 'DraftKings', fg: '#53D337' });
     expect(bookInfo('draftkings').mono).toBe('DK');
-    expect(bookInfo('ESPN').mono).toBe('EB');
+    // ESPN BET retired → theScore Bet (PENN) successor (item 7).
+    expect(bookInfo('THESCORE')).toMatchObject({ name: 'theScore Bet', mono: 'TS' });
   });
   it('degrades unknown books to a neutral chip', () => {
     const b = bookInfo('ZZZ');