Refactor and clean up codebase

- Removed unused constants and type aliases in app_spi_command_defs.h and temp_sensor.h.
- Simplified ISpiCommandHandler destructor to default.
- Eliminated redundant methods and comments in temp_sensor and usart0 files.
- Consolidated writeU32Le function to app_spi_command_defs.h for reuse.
- Updated comments for clarity and accuracy in task_manager.h and task_runner.cpp.
- Removed hardfault.h as it contained no declarations.
- Cleaned up CANFD and watchdog implementations by removing dead code and unnecessary comments.
- Updated version numbers in config.h to reflect recent changes.
- Enhanced error handling and diagnostics in hardfault handling.

GD32E508_DCU_APP/sys/hardfault.cpp

@@ -92,7 +92,6 @@ static uint32_t detectApb2Clock(void) {
 }
 
 extern "C" void HardFault_Handler_C(uint32_t *stack_frame, uint32_t lr_value) {
-    (void)lr_value;
 
     /* 确保 USART0 时钟可用 */
     volatile uint32_t *rcu_apb2en = (volatile uint32_t *)0x40021018U;
@@ -116,6 +115,8 @@ extern "C" void HardFault_Handler_C(uint32_t *stack_frame, uint32_t lr_value) {
     *usart_ctl0 = (1U << 3) | (1U << 13);  /* TE | USARTEN */
 
     rawPuts("\r\n!!! HardFault !!!\r\n");
+    rawPuts("EXC_RETURN="); rawHex32(lr_value); rawPuts("\r\n");
+    /* EXC_RETURN 解析:bit3=0(MSP)/1(PSP), bit2=0(handler mode)/1(thread mode) */
 
     if (stack_frame) {
         uint32_t pc = stack_frame[6];