fix(ops): 取消工单接口改用 @RequestBody 接收 JSON 参数

前端以 JSON body 传参，@RequestParam 无法读取导致 400 "请求参数缺失"。
新增 OpsOrderCancelReqDTO，Controller 改为 @RequestBody 风格，
与 create/assign/complete 等接口保持一致。

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

viewsh-module-ops/viewsh-module-ops-server/src/main/java/com/viewsh/module/ops/controller/admin/OpsOrderController.java

@@ -132,12 +132,9 @@ public class OpsOrderController {
 
     @PostMapping("/cancel")
     @Operation(summary = "取消工单")
-    @Parameter(name = "id", description = "工单ID", required = true)
-    @Parameter(name = "reason", description = "取消原因", required = true)
     @PreAuthorize("@ss.hasPermission('ops:order:cancel')")
-    public CommonResult<Boolean> cancelOrder(@RequestParam("id") Long id,
-                                             @RequestParam("reason") String reason) {
-        opsOrderService.cancelOrder(id, reason, OperatorTypeEnum.ADMIN, null);
+    public CommonResult<Boolean> cancelOrder(@Valid @RequestBody OpsOrderCancelReqDTO cancelReq) {
+        opsOrderService.cancelOrder(cancelReq.getId(), cancelReq.getReason(), OperatorTypeEnum.ADMIN, null);
         return success(true);
     }