feat: add direction flag to feedforward controller with init config struct

- add DM_Feedforward_Init_Config_s with Kp and dir fields
- replace plain DM_Feedforward_Kp in DM_Motor_Init_Config_s
- apply direction flag in DMMotorControl to negate feedforward when reverse
- set yaw feedforward: Kp=0.9, dir=REVERSE

application/gimbal/gimbal.c

@@ -52,7 +52,10 @@ void GimbalInit()
             .motor_type = DM_MOTOR,
         },
         .ctrl_mode = DM_MODE_VELOCITY,
-        .DM_Feedforward_Kp = 0.9f,
+        .feedforward_config = {
+            .Kp  = 0.9f,
+            .dir = OUTPUT_DIRECTION_REVERSE,
+        },
         .mit_kp = 0, .mit_kd = 0,
     };
     yaw_motor = DMMotorInit(&yaw_config);