fix: deduct raw mana cost when starting pact ritual (Issue #306)

src/lib/game/__tests__/store-actions-combat-prestige.test.ts

@@ -1,6 +1,8 @@
 import { describe, it, expect, beforeEach } from 'vitest';
 import { useCombatStore } from '../stores/combatStore';
+import { useManaStore } from '../stores/manaStore';
 import { usePrestigeStore } from '../stores/prestigeStore';
+import { getGuardianForFloor } from '../data/guardian-encounters';
 import { getFloorMaxHP } from '../utils';
 import { ErrorCode } from '../utils/result';
 
@@ -231,6 +233,7 @@ describe('PrestigeStore', () => {
 
   describe('startPactRitual', () => {
     it('should start ritual when conditions met', () => {
+      useManaStore.setState({ rawMana: 100000 });
       usePrestigeStore.setState({ defeatedGuardians: [10], signedPacts: [], insight: 10000 });
       const result = usePrestigeStore.getState().startPactRitual(10, 100000);
       expect(result.success).toBe(true);
@@ -271,6 +274,37 @@ describe('PrestigeStore', () => {
         expect(result.code).toBe(ErrorCode.INSUFFICIENT_MANA);
       }
     });
+
+    it('should deduct raw mana cost when starting ritual', () => {
+      // Get the guardian to know the exact pact cost
+      const guardian = getGuardianForFloor(10);
+      expect(guardian).not.toBeNull();
+      const cost = guardian!.pactCost;
+
+      // Set up: give mana store enough raw mana
+      useManaStore.setState({ rawMana: cost + 500 });
+      usePrestigeStore.setState({ defeatedGuardians: [10], signedPacts: [], pactSlots: 1 });
+
+      const manaBefore = useManaStore.getState().rawMana;
+      const result = usePrestigeStore.getState().startPactRitual(10, manaBefore);
+
+      expect(result.success).toBe(true);
+      expect(usePrestigeStore.getState().pactRitualFloor).toBe(10);
+      // Raw mana cost must be deducted
+      expect(useManaStore.getState().rawMana).toBe(manaBefore - cost);
+    });
+
+    it('should NOT deduct raw mana when ritual fails (e.g. not defeated)', () => {
+      useManaStore.setState({ rawMana: 100000 });
+      usePrestigeStore.setState({ defeatedGuardians: [], signedPacts: [], pactSlots: 1 });
+
+      const manaBefore = useManaStore.getState().rawMana;
+      const result = usePrestigeStore.getState().startPactRitual(10, manaBefore);
+
+      expect(result.success).toBe(false);
+      // Mana must NOT be deducted on failure
+      expect(useManaStore.getState().rawMana).toBe(manaBefore);
+    });
   });
 
   describe('cancelPactRitual', () => {

src/lib/game/stores/prestigeStore.ts

@@ -131,6 +131,11 @@ export const usePrestigeStore = create<PrestigeStore>()(
         if (rawMana < guardian.pactCost) return fail(ErrorCode.INSUFFICIENT_MANA, `Need ${guardian.pactCost} raw mana, have ${rawMana}`);
         if (state.pactRitualFloor !== null) return fail(ErrorCode.RITUAL_IN_PROGRESS, `A pact ritual is already in progress for floor ${state.pactRitualFloor}`);
 
+        // Deduct raw mana cost upfront (spec §2.2 step 7)
+        const manaStore = useManaStore.getState();
+        const deducted = manaStore.spendRawMana(guardian.pactCost);
+        if (!deducted) return fail(ErrorCode.INSUFFICIENT_MANA, `Need ${guardian.pactCost} raw mana, have ${manaStore.rawMana}`);
+
         set({
           pactRitualFloor: floor,
           pactRitualProgress: 0,