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/stores/gameStore.ts

@@ -117,7 +117,7 @@ export const useGameStore = create<GameCoordinatorStore>()(
             disciplineEffects,
           );
           const baseRegen = computeRegen(
-            { prestigeUpgrades: ctx.prestige.prestigeUpgrades, attunements: {} },
+            { prestigeUpgrades: ctx.prestige.prestigeUpgrades, attunements: ctx.attunement.attunements },
             undefined,
             disciplineEffects,
           ) * (1 + (disciplineEffects.multipliers.regenMultiplier || 0));
@@ -389,9 +389,10 @@ function buildConversionParams(
   for (const [id, state] of Object.entries(attunements)) {
     if (!state.active) continue;
     const def = ATTUNEMENTS_DEF[id];
-    if (def?.primaryManaType) {
+    if (def?.primaryManaType && def.rawManaRegen) {
+      const levelMult = Math.pow(1.5, (state.level || 1) - 1);
       grossRegen[def.primaryManaType] = (grossRegen[def.primaryManaType] || 0)
-        + (def.conversionRate || 0);
+        + def.rawManaRegen * levelMult;
     }
   }
   return { pactElementMap, grossRegen };