fix(admin): remove manual reasons and repair code creation

frontend/src/app/api/admin/codes/route.ts

@@ -28,7 +28,6 @@ const createCodesSchema = z.object({
   count: z.number().int().min(1).max(100),
   expiresAt: z.string().datetime({ offset: true }).nullable().optional(),
   note: z.string().trim().max(500).nullable().optional(),
-  reason: z.string().trim().min(1).max(500),
 });
 
 type CodeRow = {
@@ -147,7 +146,7 @@ export async function POST(request: Request) {
       "admin_create_redemption_codes",
       session,
       operationRequestId,
-      { p_codes: records, p_reason: parsed.data.reason },
+      { p_codes: records, p_reason: "admin_console_create_redemption_codes" },
     );
     const byMask = new Map<string, RedemptionCodeRecord>(
       stored.map((record) => [record.mask, record]),