Fix skill study mana deduction in skillStore.ts

- Added useManaStore import to skillStore.ts
- Added mana deduction logic in startStudyingSkill action
- Mana is now properly deducted when starting to study a skill (unless already paid)

src/app/components/LeftPanel.tsx

@@ -9,7 +9,7 @@ import { CalendarDisplay } from '@/components/game';
 import { DebugName } from '@/lib/game/debug-context';
 import { useGameStore, useManaStore, useSkillStore, useCombatStore, useCraftingStore } from '@/lib/game/stores';
 import { getUnifiedEffects } from '@/lib/game/effects';
-import { computeMaxMana, computeClickMana, getMeditationBonus } from '@/lib/game/stores';
+import { computeMaxMana, computeRegen, computeClickMana, getMeditationBonus, getIncursionStrength } from '@/lib/game/stores';
 
 export function LeftPanel() {
   const [isGathering, setIsGathering] = useState(false);
@@ -23,6 +23,9 @@ export function LeftPanel() {
   const skillTiers = useSkillStore((s) => s.skillTiers);
   const skillUpgrades = useSkillStore((s) => s.skillUpgrades);
 
+  const equippedInstances = useCraftingStore((s) => s.equippedInstances);
+  const equipmentInstances = useCraftingStore((s) => s.equipmentInstances);
+
   const gatherMana = useGameStore((s) => s.gatherMana);
   const day = useGameStore((s) => s.day);
   const hour = useGameStore((s) => s.hour);
@@ -70,20 +73,26 @@ export function LeftPanel() {
   const upgradeEffects = getUnifiedEffects({
     skillUpgrades,
     skillTiers,
-    equippedInstances: {},
-    equipmentInstances: {}
+    equippedInstances,
+    equipmentInstances,
   });
 
   const maxMana = computeMaxMana(
     { skills, skillTiers, skillUpgrades },
     upgradeEffects
   );
+  const baseRegen = computeRegen(
+    { skills, skillTiers, skillUpgrades },
+    upgradeEffects
+  );
   const clickMana = computeClickMana({
     skills,
     skillTiers,
     skillUpgrades,
   });
   const meditationMultiplier = getMeditationBonus(meditateTicks, skills, upgradeEffects.meditationEfficiency);
+  const incursionStrength = getIncursionStrength(day, hour);
+  const effectiveRegen = baseRegen * (1 - incursionStrength) * meditationMultiplier;
 
   return (
     <div className="md:w-80 space-y-4 flex-shrink-0">
@@ -91,7 +100,7 @@ export function LeftPanel() {
         <ManaDisplay
           rawMana={rawMana}
           maxMana={maxMana}
-          effectiveRegen={0} // Now calculated in page.tsx and passed
+          effectiveRegen={effectiveRegen}
           meditationMultiplier={meditationMultiplier}
           clickMana={clickMana}
           isGathering={isGathering}