feat: add DEBUG mode with host-side PID tuning, motor enable/disable protection

- Add DEBUG mode (parallel to AUTO/MANUAL) for real-time PID parameter tuning
- New 0xA8 debug frame: 12 floats for vision/motor angle PID tuning params
- DMMotorSetMode: send zero-velocity before disable, clear PID to prevent jumps
- motor_enable topic: pub from robot_cmd, sub in gimbal, controls motor on/off
- motor_pid topic: pub from robot_cmd, sub in gimbal, updates motor angle PID
- Rename DM motor enums (DM_CMD_ENABLE_MODE/DISABLE_MODE, DM_Motor_Ctrl_Mode_e)
- SwitchToAuto/Manual: re-enable motors when switching back from DEBUG mode
- Static-allocate enable_msg/pid_tune in GimbalTask to avoid stack churn
- Add docs/host_comm_guide.md with Python Tkinter tuning GUI example
- Remove ARCHITECTURE.md

application/robot_def.h

@@ -47,6 +47,19 @@ typedef struct
     uint8_t gimbal_power;
 } Gimbal_Upload_Data_s;
 
+/* ---- CMD 发布给 gimbal 的电机使能指令 ---- */
+typedef struct
+{
+    uint8_t enable;  // 0=失能, 1=使能
+} Motor_Enable_s;
+
+/* ---- CMD 发布给 gimbal 的电机角度环 PID 参数 ---- */
+typedef struct
+{
+    float yaw_Kp, yaw_Ki, yaw_Kd;
+    float pitch_Kp, pitch_Ki, pitch_Kd;
+} Motor_PID_Tune_s;
+
 #pragma pack()
 
 #endif // !ROBOT_DEF_H