fixed part role mapping to categories. set a const for categories

components/CategoryColumn.tsx

@@ -31,11 +31,15 @@ export function CategoryColumn({
       </div>
       <div className="flex-1 overflow-y-auto pr-1">
         {parts.length === 0 && (
-          <p className="text-xs text-zinc-500">No parts yet for this category.</p>
+          <p className="text-xs text-zinc-500">No parts available yet.</p>
         )}
         {!displayedPart && parts.length > 0 && (
-          <div className="w-full border border-zinc-700 rounded-md p-3 mb-2 text-center">
-            <p className="text-sm text-zinc-500 flex items-center justify-center gap-2">
+          <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={`/gunbuilder/${category.id}`}
+              className="inline-flex items-center gap-2 rounded-md border border-zinc-700 bg-zinc-900/60 px-3 py-1.5 text-xs font-medium text-zinc-200 hover:bg-zinc-800 hover:border-zinc-500 transition-colors"
+            >
               <svg
                 className="w-4 h-4"
                 fill="none"
@@ -50,7 +54,7 @@ export function CategoryColumn({
                 />
               </svg>
               Choose a Part
-            </p>
+            </Link>
           </div>
         )}
         {displayedPart && (
@@ -62,7 +66,7 @@ export function CategoryColumn({
           />
         )}
       </div>
-      {parts.length > 1 && (
+      {parts.length >= 1 && (
         <Link
           href={`/gunbuilder/${category.id}`}
           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"