fixed an vault edit error.

app/vault/[uuid]/edit/page.tsx

@@ -83,9 +83,9 @@ const CALIBERS_BY_PLATFORM: Record<
 type CaliberOption = string | "";
 
 // -----------------------------
-// Other controlled fields (optional scaffolding)
+// Build Class (controlled list)
 // -----------------------------
-const PURPOSE_OPTIONS = [
+const BUILD_CLASS_OPTIONS = [
   "Home Defense",
   "Duty / Patrol",
   "Training",
@@ -94,7 +94,7 @@ const PURPOSE_OPTIONS = [
   "Range / Fun",
 ] as const;
 
-type PurposeOption = (typeof PURPOSE_OPTIONS)[number] | "";
+type BuildClassOption = (typeof BUILD_CLASS_OPTIONS)[number] | "";
 
 function fmt(d?: string | null) {
   if (!d) return "—";
@@ -133,7 +133,7 @@ export default function EditBuildPage() {
 
     platform: PlatformOption;
     caliber: CaliberOption;
-    purpose: PurposeOption;
+    buildClass: BuildClassOption;
 
     tagsText: string; // comma-separated for MVP
     coverImageUrl: string;
@@ -201,9 +201,11 @@ export default function EditBuildPage() {
           platform: normalizedPlatform,
           caliber: normalizedCaliber,
 
-          purpose: (PURPOSE_OPTIONS.includes((dto.buildClass ?? "") as any)
+          buildClass: (BUILD_CLASS_OPTIONS.includes(
+            (dto.buildClass ?? "") as any
+          )
             ? (dto.buildClass as any)
-            : "") as PurposeOption,
+            : "") as BuildClassOption,
 
           tagsText: Array.isArray(dto.tags) ? dto.tags.join(", ") : "",
           coverImageUrl: dto.coverImageUrl ?? "",
@@ -265,7 +267,7 @@ export default function EditBuildPage() {
         isPublic: !!profile.isPublic,
 
         // Backend expects buildClass (not purpose)
-        buildClass: profile.purpose || null,
+        buildClass: profile.buildClass || null,
 
         caliber: profile.caliber || null,
         coverImageUrl: profile.coverImageUrl?.trim() || null,
@@ -454,24 +456,29 @@ export default function EditBuildPage() {
                 </div>
               </div>
 
-              {/* Purpose */}
+              {/* Build Class */}
               <div>
                 <label className="block text-xs font-medium text-white/70">
-                  Purpose
+                  Build Class
                 </label>
                 <select
-                  value={profile.purpose}
+                  value={profile.buildClass}
                   onChange={(e) =>
                     setProfile((p) =>
-                      p ? { ...p, purpose: e.target.value as PurposeOption } : p
+                      p
+                        ? {
+                            ...p,
+                            buildClass: e.target.value as BuildClassOption,
+                          }
+                        : p
                     )
                   }
                   className="mt-1 w-full rounded-md border border-white/10 bg-black/30 px-3 py-2 text-sm text-white outline-none focus:ring-1 focus:ring-amber-400/60"
                 >
                   <option value="">Select…</option>
-                  {PURPOSE_OPTIONS.map((p) => (
-                    <option key={p} value={p}>
-                      {p}
+                  {BUILD_CLASS_OPTIONS.map((c) => (
+                    <option key={c} value={c}>
+                      {c}
                     </option>
                   ))}
                 </select>
@@ -602,7 +609,7 @@ export default function EditBuildPage() {
                   {profile.caliber || "—"}
                 </span>
                 <span className="rounded-full border border-white/10 bg-white/5 px-2 py-1">
-                  {profile.purpose || "—"}
+                  {profile.buildClass || "—"}
                 </span>
               </div>