fix: apply Crafting Efficiency cost reduction to all fabrication paths

- Add getCraftingCostReduction() and applyCostReduction() helpers in crafting-fabricator.ts
- Apply cost reduction in deductMaterials() and checkFabricatorCosts()
- Apply cost reduction in startFabricatorCrafting() and cancelEquipmentCrafting() pipeline
- Update canCraftRecipe() in fabricator-recipes.ts to accept costReduction param
- Update FabricatorSubTab and MaterialRecipeCard UIs to display discounted costs
- Spec formula: actualCost = ceil(baseCost × (1 - craftingCostReduction / 100))

Fixes #316

src/lib/game/stores/pipelines/equipment-crafting.ts

@@ -10,6 +10,8 @@ import {
   deductMaterials,
   makeFabricatorProgress,
   refundFabricatorMana,
+  getCraftingCostReduction,
+  applyCostReduction,
 } from '../../crafting-fabricator';
 import { useManaStore } from '../manaStore';
 import { useCombatStore } from '../combatStore';
@@ -72,11 +74,13 @@ export function cancelEquipmentCrafting(get: GetFn, set: SetFn): void {
       const refunded = refundFabricatorMana(recipe, manaRefund, rawMana, elements);
       useManaStore.setState({ rawMana: refunded.rawMana, elements: refunded.elements });
 
-      // Refund materials
+      // Refund materials — use reduced amounts (what player actually paid)
+      const reduction = getCraftingCostReduction();
       const currentMaterials = get().lootInventory.materials;
       const refundedMaterials = { ...currentMaterials };
-      for (const [matId, amount] of Object.entries(recipe.materials)) {
-        const refundAmount = Math.floor(amount * remainingFraction);
+      for (const [matId, rawAmount] of Object.entries(recipe.materials)) {
+        const reducedAmount = applyCostReduction(rawAmount, reduction);
+        const refundAmount = Math.floor(reducedAmount * remainingFraction);
         if (refundAmount > 0) {
           refundedMaterials[matId] = (refundedMaterials[matId] || 0) + refundAmount;
         }
@@ -132,6 +136,7 @@ export function startFabricatorCrafting(recipeId: string, get: GetFn, set: SetFn
   const deducted = deductFabricatorMana(recipe, rawMana, elements);
   if (!deducted) return false;
 
+  // deductMaterials already applies cost reduction internally via getCraftingCostReduction()
   const newMaterials = deductMaterials(recipe, state.lootInventory.materials);
   const progress = makeFabricatorProgress(recipeId, recipe.equipmentTypeId, recipe.craftTime, recipe.manaCost);