fix(client): 移除 Zod default 声明，修复表单泛型冲突导致的生产环境构建失败

app/dashboard/transactions/transactions-client.tsx

@@ -87,7 +87,7 @@ export default function TransactionsPageClient({
     resolver: zodResolver(z.object({
       quantity: z.string().regex(/^-?\d+(\.\d+)?$/, '数量必须是数字'),
       price: z.string().regex(/^-?\d+(\.\d+)?$/, '价格必须是数字'),
-      fee: z.string().regex(/^-?\d+(\.\d+)?$/, '手续费必须是数字').default('0'),
+      fee: z.string().regex(/^-?\d+(\.\d+)?$/, '手续费必须是有效数字'),
       txCurrency: z.string().min(1, '交易币种不能为空'),
       executedAt: z.string(),
     })),