fixed part role calls and some other stuff

app/(builder)/builder/[categoryId]/page.tsx

@@ -5,6 +5,7 @@ import Link from "next/link";
 import { useParams, useRouter, useSearchParams } from "next/navigation";
 import { CATEGORIES } from "@/data/gunbuilderParts";
 import type { CategoryId, Part } from "@/types/gunbuilder";
+import { CATEGORY_TO_PART_ROLES } from "@/data/partRoleMappings";
 
 type ViewMode = "card" | "list";
 
@@ -44,9 +45,21 @@ const slugify = (str: string) =>
     .replace(/[^a-z0-9]+/g, "-")
     .replace(/(^-|-$)/g, "");
 
+const normalizeRole = (role: string) => role.trim().toLowerCase().replace(/_/g, "-");
+
+function getNormalizedPartRolesForCategory(categoryId: string): string[] {
+  const roles = (CATEGORY_TO_PART_ROLES as any)[categoryId] as string[] | undefined;
+  if (!roles || roles.length === 0) return [];
+  return Array.from(new Set(roles.map(normalizeRole)));
+}
+
 export default function CategoryPage() {
   const params = useParams();
   const categoryId = params.categoryId as CategoryId;
+  const partRoles = useMemo(
+    () => getNormalizedPartRolesForCategory(String(categoryId)),
+    [categoryId]
+  );
   const router = useRouter();
   const searchParams = useSearchParams();
 
@@ -102,6 +115,11 @@ export default function CategoryPage() {
         const search = new URLSearchParams();
         search.set("platform", platform);
 
+        // ✅ Scope results to this category's backend roles
+        for (const r of partRoles) {
+          search.append("partRoles", r);
+        }
+
         const url = `${API_BASE_URL}/api/products?${search.toString()}`;
 
         const res = await fetch(url, { signal: controller.signal });
@@ -136,7 +154,7 @@ export default function CategoryPage() {
     fetchCategoryParts();
 
     return () => controller.abort();
-  }, [categoryId, platform]);
+  }, [categoryId, platform, partRoles]);
 
   //  persist build to localStorage whenever it changes
   useEffect(() => {