fix: resolve 7 medium-priority bugs from audit #372

- #371: Replace Math.random() with seeded PRNG in getSpireEnemyArmor/Barrier
- #370: Add mana refund when cancelling pact ritual in cancelPactRitual
- #367: Add ENCHANT_MASTERY check for design slot 2 in crafting store
- #364: Fix useGameDerived to read crafting data from useCraftingStore
- #363: Clamp recovery room regen delta to prevent negative mana loss
- #365: Add shield/barrier/healthRegen fields to all procedural guardians
- #362: Refactor enchanting tick pipeline to return writes instead of direct store calls

Extracted procedural guardian generators into guardian-procedural.ts to stay under 400-line limit.

All 1158 tests pass.

src/lib/game/stores/prestigeStore.ts

@@ -144,6 +144,15 @@ export const usePrestigeStore = create<PrestigeStore>()(
       },
 
       cancelPactRitual: () => {
+        const state = get();
+        if (state.pactRitualFloor !== null) {
+          const guardian = getGuardianForFloor(state.pactRitualFloor);
+          if (guardian) {
+            useManaStore.setState((s) => ({
+              rawMana: s.rawMana + guardian.pactCost,
+            }));
+          }
+        }
         set({
           pactRitualFloor: null,
           pactRitualProgress: 0,