feat: split skills-v2-defs into category modules and fix export

- Split 636-line skills-v2-defs.ts into 9 category files (all under 400 lines)
- Add skills-v2-registry.ts to build SKILLS_V2 flat record from modules
- Fix missing re-export of SKILLS_V2 from skills-v2.ts
- Fix clickMana clamping: remove Math.round to allow fractional values
- Fix golemDuration clamping: remove Math.round to allow fractional values
- Fix guardianConstructs effect: duration uses 'add' mode instead of 'multiply'
- All 70 existing tests pass

src/lib/game/constants/skills-v2.ts

@@ -0,0 +1,269 @@
+import type { SkillV2Def, SkillEffect, StatKey, ComputedStats } from './skills-v2-types';
+import { SKILLS_V2 } from './skills-v2-defs';
+
+// Re-export individual skills from category modules
+export {
+  manaWell,
+  manaFlow,
+  manaOverflow,
+  manaTap,
+  manaSurge,
+  manaSpring,
+  quickLearner,
+  focusedMind,
+  knowledgeRetention,
+  meditation,
+  deepTrance,
+  voidMeditation,
+} from './skills-core';
+
+export {
+  enchanting,
+  efficientEnchant,
+  enchantSpeed,
+  essenceRefining,
+  disenchanting,
+} from './skills-enchant';
+
+export {
+  arcaneFury,
+  combatTraining,
+  precision,
+  elementalMastery,
+  attackSpeed,
+  armorPiercing,
+  spellDamage,
+} from './skills-combat';
+
+export {
+  golemMastery,
+  golemEfficiency,
+  golemLongevity,
+} from './skills-golemancy';
+
+export {
+  invocation,
+  pactMastery,
+  guardianLore,
+} from './skills-invocation';
+
+export {
+  effCrafting,
+  fieldRepair,
+} from './skills-crafting';
+
+export {
+  fireManaCap,
+  waterManaCap,
+  airManaCap,
+  earthManaCap,
+  lightManaCap,
+  darkManaCap,
+  deathManaCap,
+  metalManaCap,
+  sandManaCap,
+  lightningManaCap,
+  transferenceManaCap,
+} from './skills-element-caps';
+
+export {
+  pactWeaving,
+  guardianConstructs,
+  enchantedGolemancy,
+} from './skills-hybrid';
+
+export {
+  researchManaSpells,
+  researchFireSpells,
+  researchWaterSpells,
+  researchAirSpells,
+  researchEarthSpells,
+  researchLightSpells,
+  researchDarkSpells,
+  researchLifeDeathSpells,
+  researchAdvancedFire,
+  researchAdvancedWater,
+  researchAdvancedAir,
+  researchAdvancedEarth,
+  researchAdvancedLight,
+  researchAdvancedDark,
+  researchMasterFire,
+  researchMasterWater,
+  researchMasterEarth,
+  researchDamageEffects,
+  researchCombatEffects,
+  researchManaEffects,
+  researchAdvancedManaEffects,
+  researchUtilityEffects,
+  researchSpecialEffects,
+  researchOverpower,
+  researchMetalSpells,
+  researchSandSpells,
+  researchLightningSpells,
+  researchAdvancedMetal,
+  researchAdvancedSand,
+  researchAdvancedLightning,
+  researchMasterMetal,
+  researchMasterSand,
+  researchMasterLightning,
+  researchTransferenceSpells,
+  researchAdvancedTransference,
+  researchMasterTransference,
+  researchAdvancedFireCap,
+  researchAdvancedWaterCap,
+  researchAdvancedAirCap,
+  researchAdvancedEarthCap,
+  researchAdvancedLightCap,
+  researchAdvancedDarkCap,
+  researchAdvancedDeathCap,
+  researchMasterFireCap,
+  researchMasterWaterCap,
+  researchMasterAirCap,
+  researchMasterEarthCap,
+  researchMasterLightCap,
+  researchMasterDarkCap,
+  researchMasterDeathCap,
+  researchMetalCapacity,
+  researchAdvancedMetalCap,
+  researchSandCapacity,
+  researchAdvancedSandCap,
+  researchLightningCapacity,
+  researchAdvancedLightningCap,
+  researchCrystalCapacity,
+  researchAdvancedCrystalCap,
+  researchStellarCapacity,
+  researchAdvancedStellarCap,
+  researchVoidCapacity,
+  researchAdvancedVoidCap,
+} from './skills-research';
+
+export { SKILLS_V2 };
+
+// Default Base Stats
+export const BASE_STATS: ComputedStats = {
+  maxMana: 100,
+  manaRegen: 2,
+  clickMana: 1,
+  elementCap: 10,
+  studySpeed: 1,
+  studyCostMult: 1,
+  meditationEfficiency: 1,
+  enchantCapacity: 100,
+  enchantSpeed: 1,
+  enchantPower: 1,
+  disenchantRecovery: 1,
+  baseDamage: 5,
+  damageMultiplier: 1,
+  attackSpeed: 1,
+  critChance: 0,
+  critMultiplier: 1.5,
+  armorPierce: 0,
+  insightGain: 1,
+  golemDamage: 1,
+  golemDuration: 1,
+  pactMultiplier: 1,
+  conversionRate: 1,
+  spellDamage: 1,
+  guardianDamage: 1,
+  craftSpeed: 1,
+  repairSpeed: 1,
+  fireCap: 0, waterCap: 0, airCap: 0, earthCap: 0,
+  lightCap: 0, darkCap: 0, deathCap: 0,
+  metalCap: 0, sandCap: 0, lightningCap: 0,
+  transferenceCap: 0, crystalCap: 0, stellarCap: 0, voidCap: 0,
+  elementalDamage: 1,
+};
+
+const ELEMENT_CAP_STATS: Record<string, keyof ComputedStats> = {
+  fire: 'fireCap', water: 'waterCap', air: 'airCap', earth: 'earthCap',
+  light: 'lightCap', dark: 'darkCap', death: 'deathCap', metal: 'metalCap',
+  sand: 'sandCap', lightning: 'lightningCap', transference: 'transferenceCap',
+  crystal: 'crystalCap', stellar: 'stellarCap', void: 'voidCap',
+};
+
+/**
+ * Compute all game stats from skill levels.
+ */
+export function computeStats(
+  skills: Record<string, number>,
+  prestigeUpgrades: Record<string, number> = {}
+): ComputedStats {
+  const stats: ComputedStats = { ...BASE_STATS };
+
+  for (const [skillId, level] of Object.entries(skills)) {
+    if (level <= 0) continue;
+    const def = SKILLS_V2[skillId];
+    if (!def) continue;
+    for (const effect of def.effects) {
+      const key = effect.stat as keyof ComputedStats;
+      const currentVal = stats[key] as number;
+      if (effect.mode === 'add') {
+        (stats[key] as number) = currentVal + effect.valuePerLevel * level;
+      } else {
+        const perLevelMultiplier = 1 + effect.valuePerLevel;
+        let result = currentVal;
+        for (let i = 0; i < level; i++) result *= perLevelMultiplier;
+        (stats[key] as number) = result;
+      }
+    }
+  }
+
+  if (prestigeUpgrades.manaWell) stats.maxMana += prestigeUpgrades.manaWell * 500;
+  if (prestigeUpgrades.manaFlow) stats.manaRegen += prestigeUpgrades.manaFlow * 0.5;
+  if (prestigeUpgrades.elementalAttune) stats.elementCap += prestigeUpgrades.elementalAttune * 25;
+  if (prestigeUpgrades.pactBinding) stats.pactMultiplier += prestigeUpgrades.pactBinding * 0.1;
+  if (prestigeUpgrades.insightAmp) stats.insightGain *= 1 + prestigeUpgrades.insightAmp * 0.25;
+
+  let elementCapFromSkills = 0;
+  for (const [, statKey] of Object.entries(ELEMENT_CAP_STATS)) {
+    const val = stats[statKey] as number;
+    if (val > 0) elementCapFromSkills += val;
+  }
+  if (elementCapFromSkills > 0) stats.elementCap += elementCapFromSkills;
+
+  stats.maxMana = Math.max(1, Math.round(stats.maxMana));
+  stats.manaRegen = Math.round(stats.manaRegen * 100) / 100;
+  stats.clickMana = Math.max(1, stats.clickMana);
+  stats.elementCap = Math.max(10, Math.round(stats.elementCap));
+  stats.baseDamage = Math.max(1, Math.round(stats.baseDamage));
+  stats.critChance = Math.min(1, Math.max(0, stats.critChance));
+  stats.armorPierce = Math.min(1, Math.max(0, stats.armorPierce));
+  stats.attackSpeed = Math.max(0.1, stats.attackSpeed);
+  stats.insightGain = Math.max(0, stats.insightGain);
+  stats.golemDamage = Math.max(0.1, stats.golemDamage);
+  stats.golemDuration = Math.max(1, stats.golemDuration);
+  stats.enchantCapacity = Math.max(10, Math.round(stats.enchantCapacity));
+  stats.conversionRate = Math.max(0, stats.conversionRate);
+
+  return stats;
+}
+
+/**
+ * Get the base key for a tiered skill (strips _tN suffix).
+ */
+export function getBaseSkillId(skillId: string): string {
+  const match = skillId.match(/^(.+?)_t(\d+)$/);
+  return match ? match[1] : skillId;
+}
+
+/**
+ * Check if a skill has prerequisites that are met.
+ */
+export function hasPrerequisites(
+  skills: Record<string, number>,
+  prerequisites?: Record<string, number>
+): boolean {
+  if (!prerequisites) return true;
+  for (const [reqId, reqLevel] of Object.entries(prerequisites)) {
+    if ((skills[reqId] || 0) < reqLevel) return false;
+  }
+  return true;
+}
+
+/** Legacy compat wrapper */
+export function computeStatsLegacy(state: {
+  skills: Record<string, number>;
+  prestigeUpgrades?: Record<string, number>;
+}): ComputedStats {
+  return computeStats(state.skills, state.prestigeUpgrades || {});
+}