fix: 有限存在超时后完整恢复无车状态

set_loops_relay_off 之后补充：
- loop_VD_FLAG = 0  → 无车 → 绿灯灭 (poll_green_led 自动)
- loop_FLAG_OUT = 1  → 触发正常离开输出
- LC_HOLD = 0        → 清除安全保持
- loop_ORG_CNT/SUM=0  → 重置基线跟踪

vd960Loop/utilities/at32f421_freertos_demo/src/TaskLoop.c

@@ -300,6 +300,11 @@ void TMR15_GLOBAL_IRQHandler(void)
                         unit->Hold_CNT = 0;
                         if (unit->loop_VD_FLAG) {
                             set_loops_relay_off(unit->loop_num);
+                            unit->loop_VD_FLAG  = 0;
+                            unit->loop_FLAG_OUT = 1;
+                            unit->LC_HOLD  = 0;
+                            unit->loop_ORG_CNT = 0;
+                            unit->loop_ORG_SUM = 0;
                         }
                     }
                 }