feat(device): 新增远程拍照功能

- 新增设备端与家属端远程拍照接口
- 新增截图实体字段（原始文件名、MIME类型、扩展名）
- 补充截图上传信息记录
- 提取设备操作指令常量

src/main/java/com/youlai/boot/client/controller/ClientDeviceOpsController.java

@@ -143,6 +143,24 @@ public class ClientDeviceOpsController {
         }
     }
 
+    @Operation(summary = "远程拍照（家属端）")
+    @PreAuthorize("isAuthenticated()")
+    @PostMapping("/take_photo")
+    public Result<?> takePhoto(
+            @Parameter(description = "设备序列号") @RequestParam("sn") String sn
+    ) {
+        try {
+            checkBound(sn);
+            boolean result = deviceService.takePhoto(sn);
+            return Result.judge(result);
+        } catch (BusinessException be) {
+            return Result.failed(be.getMessage());
+        } catch (Exception e) {
+            log.error("remoteCamera error, sn: {}", sn, e);
+            return Result.failed("设备截图失败: " + e.getMessage());
+        }
+    }
+
     @Operation(summary = "设备重启（家属端）")
     @PreAuthorize("isAuthenticated()")
     @PostMapping("/reboot")