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

app/gunbuilder/admin/category-mappings/page.tsx

@@ -27,16 +27,27 @@ type UpsertRequest = {
 // Keep this in sync with your backend `partRole` values
 const PART_ROLE_OPTIONS = [
   { value: "", label: "— Unmapped —" },
+  // Lower / fire control
+  { value: "lower-receiver", label: "Lower Receiver" },
+  { value: "lower-parts-kit", label: "Lower Parts Kit" },
+  { value: "trigger", label: "Trigger / Trigger Kit" },
+  { value: "pistol-grip", label: "Pistol Grip" },
+  { value: "safety-selector", label: "Safety Selector" },
+
+  // Upper
   { value: "upper-receiver", label: "Upper Receiver" },
   { value: "barrel", label: "Barrel" },
   { value: "handguard", label: "Handguard" },
-  { value: "charging-handle", label: "Charging Handle" },
-  { value: "buffer-kit", label: "Buffer Kit" },
-  { value: "lower-parts-kit", label: "Lower Parts Kit" },
-  { value: "sight", label: "Sight / Optic" },
-  { value: "lower-receiver", label: "Lower Receiver" },
-  { value: "optic", label: "Optic" },
+  { value: "gas-system", label: "Gas System / Gas Block" },
+  { value: "muzzle-device", label: "Muzzle Device" },
+  { value: "suppressor", label: "Suppressor" },
+
+  // Furniture / sights / optics
   { value: "stock", label: "Stock" },
+  { value: "buffer-kit", label: "Buffer Kit" },
+  { value: "charging-handle", label: "Charging Handle" },
+  { value: "sight", label: "Iron / Backup Sight" },
+  { value: "optic", label: "Optic" },
   { value: "other", label: "Other / Ignore" },
 ];