fix(export): Store variantIndex in GearItem for accurate export

Add variantIndex to GearItem type so gear variants are preserved
through export/import cycle. Previously, export relied on sprite
matching which could fail and default to wrong variant (index 0).

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: justjuangui

src/lib/export/collectors.ts

@@ -29,15 +29,21 @@ import { GEAR_SLOT_MAP, SKILL_SLOT_MAP, RARITY_MAP } from "./format";
 // ============================================================================
 
 /**
- * Find the variant index for a gear item by matching its properties
+ * Get the variant index for a gear item
+ * Uses stored variantIndex, with fallback to sprite matching for backwards compatibility
  */
 function findVariantIndex(gearItem: GearItem, gearsHelper: GearsHelper): number {
+  // Use stored variant index if available
+  if (gearItem.variantIndex !== undefined) {
+    return gearItem.variantIndex;
+  }
+
+  // Fallback to sprite matching for backwards compatibility
   const def = gearsHelper.getGearDefinitionById(gearItem.defId);
   if (!def || !def.variants || def.variants.length === 0) {
     return 0;
   }
 
-  // Try to match by sprite
   if (gearItem.sprite) {
     for (let i = 0; i < def.variants.length; i++) {
       if (def.variants[i].value.sprite === gearItem.sprite) {
@@ -46,7 +52,6 @@ function findVariantIndex(gearItem: GearItem, gearsHelper: GearsHelper): number
     }
   }
 
-  // Default to first variant
   return 0;
 }
 

src/lib/hellclock/gears.ts

@@ -60,6 +60,7 @@ export type GearDefinition = {
 export type GearRoot = { Gear: GearDefinition[] };
 export type GearItem = {
   defId: number;
+  variantIndex: number;
   slot: GearSlot;
   tier: number;
   visualTier: number;
@@ -216,6 +217,7 @@ export class GearsHelper {
 
     return {
       defId: gd.id,
+      variantIndex,
       slot: gd.slot,
       tier: gd.tier,
       visualTier: gd.visualTier ?? gd.tier,
@@ -261,6 +263,7 @@ export class GearsHelper {
             // If the gear definition has no variants, we create a default item with no mods
             items.push({
               defId: gd.id,
+              variantIndex: 0,
               slot: gd.slot,
               tier: gd.tier,
               visualTier: gd.visualTier ?? gd.tier,
@@ -288,7 +291,7 @@ export class GearsHelper {
           }
           return;
         }
-        gd.variants.forEach((variant) => {
+        gd.variants.forEach((variant, variantIdx) => {
           const rarity = blessed
             ? this.gearRarity.blessedGearRarity
             : undefined;
@@ -303,6 +306,7 @@ export class GearsHelper {
           });
           items.push({
             defId: gd.id,
+            variantIndex: variantIdx,
             slot: gd.slot,
             tier: gd.tier,
             visualTier: gd.visualTier ?? gd.tier,