Session 15: Intelligence hardening — park factors, weather, Tank01 prefetch, pace factors, signal audit, founder pricing fix (1405 tests)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/data/parkFactors.js

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+/**
+ * MLB park factors (Session 15).
+ *
+ * Source: FanGraphs 2024-25 park factor data (three-year weighted
+ * average — FanGraphs methodology). Numbers indexed to 100 = league
+ * average. Pulled from https://www.fangraphs.com/guts.aspx (Park
+ * Factors tab) 2025-04. Update annually; the rolling-three-year
+ * window means values move slowly.
+ *
+ * Fields per park:
+ *   hr — home run factor (Coors ~128 means HRs are 28% more likely;
+ *        Oracle/SF ~85 means 15% less likely)
+ *   h  — overall hit factor
+ *   r  — runs factor
+ *
+ * The feature extractor reads this via `getParkFactor(homeTeam)`
+ * during the MLB branch and merges hr/h/r as `park_hr`, `park_h`,
+ * `park_r` so the grading engine + reasoning builder can read them
+ * without re-doing the lookup.
+ *
+ * Indexing convention: home-team abbreviation. The road team plays
+ * at the home team's park, so a Yankees-at-Angels game uses LAA's
+ * park factors regardless of whose batter you're grading.
+ */
+
+const PARK_FACTORS = Object.freeze({
+  // AL East
+  BAL: { hr: 109, h: 100, r: 102 },  // Camden Yards — left field wall changes leveled off post-2022
+  BOS: { hr: 100, h: 108, r: 106 },  // Fenway — Monster boosts singles/doubles, suppresses HR
+  NYY: { hr: 114, h: 101, r: 104 },  // Yankee Stadium — short porch in right
+  TB:  { hr:  93, h:  96, r:  94 },  // Tropicana — neutral-to-pitcher dome
+  TOR: { hr: 106, h: 101, r: 102 },  // Rogers Centre — slight HR boost
+
+  // AL Central
+  CHW: { hr: 109, h: 102, r: 105 },  // Guaranteed Rate Field
+  CLE: { hr:  96, h:  99, r:  98 },  // Progressive Field — slight pitcher park
+  DET: { hr:  90, h: 100, r:  97 },  // Comerica — deep alleys, HR-suppressed
+  KC:  { hr:  93, h: 103, r: 101 },  // Kauffman — XBH-friendly, HR-neutral
+  MIN: { hr: 105, h: 100, r: 101 },  // Target Field
+
+  // AL West
+  HOU: { hr: 100, h: 101, r: 101 },  // Minute Maid — Crawford boxes ~neutral, dome
+  LAA: { hr:  97, h:  98, r:  98 },  // Angel Stadium
+  OAK: { hr:  91, h:  95, r:  92 },  // Coliseum — extreme pitcher park
+  SEA: { hr:  96, h:  98, r:  96 },  // T-Mobile Park — marine air
+  TEX: { hr: 104, h: 102, r: 103 },  // Globe Life — climate-controlled since 2020
+
+  // NL East
+  ATL: { hr: 103, h: 100, r: 101 },  // Truist Park
+  MIA: { hr:  89, h:  97, r:  94 },  // loanDepot park — deep alleys
+  NYM: { hr:  95, h:  99, r:  97 },  // Citi Field — slight pitcher
+  PHI: { hr: 109, h: 100, r: 102 },  // Citizens Bank Park — bandbox right field
+  WSH: { hr: 100, h: 100, r: 100 },  // Nationals Park — true neutral
+
+  // NL Central
+  CHC: { hr: 106, h: 100, r: 102 },  // Wrigley — wind-driven swings; multi-year average
+  CIN: { hr: 113, h: 102, r: 105 },  // Great American — top-3 HR park most years
+  MIL: { hr: 104, h: 100, r: 101 },  // American Family Field
+  PIT: { hr:  96, h: 101, r:  99 },  // PNC Park — XBH-favorable, HR-suppressed
+  STL: { hr:  93, h:  98, r:  96 },  // Busch — neutral-to-pitcher
+
+  // NL West
+  ARI: { hr: 100, h:  98, r:  98 },  // Chase Field — humidor since 2018
+  COL: { hr: 128, h: 112, r: 120 },  // Coors Field — altitude. Single biggest park effect.
+  LAD: { hr: 102, h:  99, r:  99 },  // Dodger Stadium
+  SD:  { hr:  95, h:  97, r:  95 },  // Petco — marine air pitcher park
+  SF:  { hr:  85, h:  96, r:  92 },  // Oracle Park — Bay winds suppress HRs heavily
+});
+
+const NEUTRAL = Object.freeze({ hr: 100, h: 100, r: 100 });
+
+function normalizeTeamCode(team) {
+  if (!team) return null;
+  return String(team).trim().toUpperCase();
+}
+
+/**
+ * getParkFactor — lookup by home-team code. Returns null for unknown
+ * teams so the feature extractor can drop the signal entirely rather
+ * than falsely report "neutral park" on a misspelled abbreviation.
+ *
+ * @param {string} homeTeam — three-letter team code (BAL, NYY, COL, ...)
+ * @returns {{hr:number, h:number, r:number}|null}
+ */
+function getParkFactor(homeTeam) {
+  const code = normalizeTeamCode(homeTeam);
+  if (!code) return null;
+  return PARK_FACTORS[code] || null;
+}
+
+/**
+ * Convenience — when you want a guaranteed object (e.g. arithmetic
+ * downstream that can't handle null). Falls back to league-neutral.
+ * Prefer getParkFactor + explicit-null branching in code; this is
+ * for tests and downstream services that prefer 100s over null.
+ */
+function getParkFactorOrNeutral(homeTeam) {
+  return getParkFactor(homeTeam) || NEUTRAL;
+}
+
+module.exports = {
+  PARK_FACTORS,
+  NEUTRAL,
+  getParkFactor,
+  getParkFactorOrNeutral,
+  __internals: { normalizeTeamCode },
+};