fixed platform selector and part selector

components/CategoryColumn.tsx

@@ -9,6 +9,7 @@ interface CategoryColumnProps {
   parts: Part[];
   selectedPartId?: string;
   onSelectPart: (partId: string) => void;
+  platform?: string;
 }
 
 export function CategoryColumn({
@@ -16,6 +17,7 @@ export function CategoryColumn({
   parts,
   selectedPartId,
   onSelectPart,
+  platform,
 }: CategoryColumnProps) {
   // Show selected part if available, otherwise show placeholder
   const displayedPart = selectedPartId
@@ -37,8 +39,11 @@ export function CategoryColumn({
           <div className="w-full border border-zinc-700 rounded-md p-3 mb-2 flex items-center justify-between gap-3">
             <p className="text-sm text-zinc-500">No part selected</p>
             <Link
-              href={`/builder/${category.id}`}
-              className="inline-flex items-center gap-2 rounded-md border border-zinc-700 bg-zinc-900/60 px-3 py-1.5 text-xs font-medium text-zinc-200 hover:bg-zinc-800 hover:border-zinc-500 transition-colors"
+              href={{
+                pathname: `/builder/${category.id}`,
+                query: platform ? { platform } : {},
+              }}
+              className="inline-flex w-full items-center justify-center rounded-md border border-zinc-700 bg-zinc-900 px-4 py-2 text-xs font-semibold text-zinc-100 hover:bg-zinc-800 hover:border-zinc-600 transition-colors"
             >
               <svg
                 className="w-4 h-4"
@@ -68,7 +73,10 @@ export function CategoryColumn({
       </div>
       {parts.length >= 1 && (
         <Link
-          href={`/builder/${category.id}`}
+          href={{
+            pathname: `/builder/${category.id}`,
+            query: platform ? { platform } : {},
+          }}
           className="mt-2 w-full rounded-md border border-zinc-700 bg-zinc-900/50 px-3 py-2 text-xs font-medium text-zinc-300 hover:bg-zinc-800 hover:border-zinc-600 transition-colors text-center"
         >
           View All ({parts.length})