fixed a hydratioin issue

app/(app)/(builder)/builder/page.tsx

@@ -420,21 +420,22 @@ export default function GunbuilderPage() {
   
         const data: GunbuilderProductFromApi[] = await res.json();
 
-        const hydrated: Part[] = data
+        // Map products by id for quick lookup
-        .map((p): Part | null => {
+        const byId = new Map<string, GunbuilderProductFromApi>();
-          const normalizedRole = (p.partRole ?? "")
+        for (const p of data) byId.set(String(p.id), p);
-            .trim()
-            .toLowerCase()
-            .replace(/_/g, "-");
         
-          const categoryId = resolveCategoryId(normalizedRole);
+        // Build the hydrated parts by iterating the BUILD STATE (slot -> id)
-          if (!categoryId) return null;
+        const hydrated: Part[] = Object.entries(build)
+          .filter(([, id]) => Boolean(id))
+          .map(([slot, id]) => {
+            const p = byId.get(String(id));
+            if (!p) return null;
         
             const buyUrl = p.buyUrl ?? undefined;
         
             return {
               id: String(p.id),
-            categoryId,
+              categoryId: slot as any, // ✅ slot is the source of truth
               name: p.name,
               brand: p.brand,
               price: p.price ?? 0,
@@ -442,11 +443,12 @@ export default function GunbuilderPage() {
               affiliateUrl: buyUrl,
               url: buyUrl,
               notes: undefined,
-          };
+            } as Part;
           })
-        .filter((p): p is Part => p !== null);
+          .filter((x): x is Part => x !== null);
         
         setParts(hydrated);
+        
       } catch (err: any) {
         if (err?.name === "AbortError") return;
         setError(err?.message ?? "Failed to hydrate selected parts");