fix: resolve elemental mana conversion pause bug (#348)

Two root causes fixed:
1. gameStore.ts: computeRegen now receives actual attunements instead of empty {}, so rawGrossRegen includes attunement contributions (was ~2/hr, now correct 3000+/hr)
2. gameStore.ts buildConversionParams: use rawManaRegen with level scaling (1.5^(level-1)) instead of conversionRate for per-element grossRegen
3. LeftPanel.tsx: same grossRegen fix + include attunement regen in rawGrossRegen display
4. ElementStatsSection.tsx: same grossRegen fix
5. useGameDerived.ts: pass actual attunements to computeRegen for baseRegen calculation

Added regression test: conversion-pause-bug-regression.test.ts (7 tests)

src/lib/game/hooks/useGameDerived.ts

@@ -6,6 +6,7 @@ import { useGameStore } from '../stores/gameStore';
 import { useManaStore } from '../stores/manaStore';
 import { useCombatStore } from '../stores/combatStore';
 import { usePrestigeStore } from '../stores/prestigeStore';
+import { useAttunementStore } from '../stores/attunementStore';
 import { computeEffects } from '../effects/upgrade-effects';
 import {
   computeMaxMana,
@@ -18,6 +19,7 @@ import {
   getElementalBonus,
 } from '../utils';
 import { computePactMultiplier, computePactInsightMultiplier } from '../utils/pact-utils';
+
 import { ELEMENTS, SPELLS_DEF, getStudySpeedMultiplier, getStudyCostMultiplier, HOURS_PER_TICK, TICK_MS } from '../constants';
 import { getGuardianForFloor } from '../data/guardian-encounters';
 import { hasSpecial, SPECIAL_EFFECTS } from '../effects/special-effects';
@@ -32,6 +34,7 @@ export function useManaStats() {
   const meditateTicks = useManaStore((s) => s.meditateTicks);
   const day = useGameStore((s) => s.day);
   const hour = useGameStore((s) => s.hour);
+  const attunements = useAttunementStore((s) => s.attunements);
 
   const disciplineEffects = useMemo(
     () => computeDisciplineEffects(),
@@ -49,8 +52,8 @@ export function useManaStats() {
   );
 
   const baseRegen = useMemo(
-    () => computeRegen({ prestigeUpgrades, attunements: {} } as any, upgradeEffects),
-    [prestigeUpgrades, upgradeEffects]
+    () => computeRegen({ prestigeUpgrades, attunements } as any, upgradeEffects),
+    [prestigeUpgrades, upgradeEffects, attunements]
   );
 
   const clickMana = useMemo(