✨ feat(routes): 优化路线查询参数验证

- 为vehicleType添加枚举限制，仅允许BUS、MINIBUS、CAR、BUSINESS类型
- 为travelMode添加枚举限制，仅允许CARPOOL、CHARTER类型
- 增强参数合法性校验，减少无效查询请求

src/server/modules/routes/route.schema.ts

@@ -97,8 +97,8 @@ export const getRouteSchema = z.object({
 // 路线列表查询Schema
 export const listRoutesSchema = z.object({
   keyword: z.string().optional(),
-  vehicleType: z.string().optional(),
-  travelMode: z.string().optional(),
+  vehicleType: z.enum([VehicleType.BUS, VehicleType.MINIBUS, VehicleType.CAR, VehicleType.BUSINESS]).optional(),
+  travelMode: z.enum([TravelMode.CARPOOL, TravelMode.CHARTER]).optional(),
   routeType: z.enum(['departure', 'return']).optional(),
   minPrice: z.coerce.number().min(0).optional(),
   maxPrice: z.coerce.number().min(0).optional(),