feat(DCU_APP): 添加CPU负载监控和EtherCAT诊断功能

- 在DCU_APP项目中添加cpu_load.h和cpu_load.cpp模块用于CPU负载率监测
- 修改csolution配置将构建目标从Debug切换为Release
- 在EtherCAT PDO协议栈中新增段5诊断区（632-639字节），包含负载率和序列号
- 在所有关键中断服务程序中添加CpuLoad::isrEnter()/isrExit()钩子用于准确统计中断占用
- 增强EtherCAT同步中断处理，改进AL事件掩码守护机制，修复OP状态下PDI中断门控问题
- 解决SSC源码中指针地址对齐警告和打包成员访问警告问题
- 在主循环中集成CPU负载率采样tick()调用，实现1秒滚动窗口统计

BREAKING CHANGE: 构建配置从Debug改为Release，EtherCAT协议栈增加新的诊断数据区

GD32E508_DCU_APP/comm/ethercat_sync.cpp

@@ -9,6 +9,7 @@
 #include "comm/ethercat_sync.h"
 #include "sys/config.h"
 #include "main.h"   /* g_app_uptime_sec */
+#include "sys/cpu_load.h"
 #include <cstdio>
 
 extern "C" {
@@ -168,13 +169,23 @@ extern "C" {
 
 #if (CONFIG_ETHERCAT_SYNC_MODE == 0)
 __attribute__((section(".ramfunc"), noinline))
-void EXTI0_IRQHandler(void)  { EthercatSync::onSync0Exti(); }
-void EXTI1_IRQHandler(void)  { EthercatSync::onEscIrqExti(); }
-void EXTI2_IRQHandler(void)  { EthercatSync::onSync1Exti(); }
+void EXTI0_IRQHandler(void)
+{
+    CpuLoad::isrEnter();
+    EthercatSync::onSync0Exti();
+    CpuLoad::isrExit();
+}
+void EXTI1_IRQHandler(void)  { CpuLoad::isrEnter(); EthercatSync::onEscIrqExti(); CpuLoad::isrExit(); }
+void EXTI2_IRQHandler(void)  { CpuLoad::isrEnter(); EthercatSync::onSync1Exti(); CpuLoad::isrExit(); }
 #else
-void TIMER0_UP_TIMER9_IRQHandler(void) { EthercatSync::onTimerIrq(); }
-void EXTI1_IRQHandler(void)  { EthercatSync::onEscIrqExti(); }
-void EXTI2_IRQHandler(void)  { EthercatSync::onSync1Exti(); }
+void TIMER0_UP_TIMER9_IRQHandler(void)
+{
+    CpuLoad::isrEnter();
+    EthercatSync::onTimerIrq();
+    CpuLoad::isrExit();
+}
+void EXTI1_IRQHandler(void)  { CpuLoad::isrEnter(); EthercatSync::onEscIrqExti(); CpuLoad::isrExit(); }
+void EXTI2_IRQHandler(void)  { CpuLoad::isrEnter(); EthercatSync::onSync1Exti(); CpuLoad::isrExit(); }
 #endif
 
 /* ---- SSC 诊断对象 0x2000 的 C 侧访问 (dc_app.c APPL_InputMapping 每周期拉取) ---- */