feat: add ESP32 BTS7960 motor controller with web interface

- Implement MotorController class with PWM speed control (0-100%)
- Add bidirectional control (forward/reverse) via LEDC PWM at 20kHz
- Include optional current sensing and stall detection
- Create responsive web UI with speed slider and direction buttons
- Configure WiFi with static IP (10.81.2.185)
- Use built-in WebServer library for ESP32 Arduino 3.x compatibility

include/motor.h

@@ -0,0 +1,41 @@
+#ifndef MOTOR_H
+#define MOTOR_H
+
+#include <Arduino.h>
+#include "config.h"
+
+class MotorController {
+public:
+    void begin();
+    void setSpeed(int speed);        // 0-100 percentage
+    void setDirection(int dir);      // -1=reverse, 0=stop, 1=forward
+    void stop();
+    void update();                   // Call in loop() for stall detection
+    
+    int getSpeed();
+    int getDirection();
+    float getCurrentRight();         // Current in amps (forward direction)
+    float getCurrentLeft();          // Current in amps (reverse direction)
+    float getCurrentActive();        // Current from active direction
+    bool isStalled();                // True if stall detected
+    
+    // Callback for stall events
+    void setStallCallback(void (*callback)(float current));
+
+private:
+    int _speed = 0;
+    int _direction = 0;
+    float _currentRight = 0;
+    float _currentLeft = 0;
+    bool _stalled = false;
+    unsigned long _stallStartTime = 0;
+    void (*_stallCallback)(float current) = nullptr;
+    
+    void applyMotorState();
+    float readCurrentSense(int pin);
+    void checkStall();
+};
+
+extern MotorController motor;
+
+#endif