feat: add dual BTS7960 motor driver support

- Refactor MotorController to parameterized class with MotorPins struct
- Add motor1 and motor2 instances with shared enable pins (GPIO 14, 27)
- Motor 2 uses GPIO 32/33 for PWM, GPIO 36/39 for current sense
- Update web UI with side-by-side dual motor control panels
- Add per-motor API endpoints (/motor1/*, /motor2/*)
- Add emergency stop button for both motors
- Legacy endpoints map to motor1 for backwards compatibility
- Update readme and AGENTS.md documentation

src/main.cpp

@@ -4,10 +4,16 @@
 #include "motor.h"
 #include "webserver.h"
 
-// Called when motor stall is detected
-void onMotorStall() {
-    Serial.println("Stall callback triggered - stopping motor!");
-    motor.stop();
+// Called when motor 1 stall is detected
+void onMotor1Stall() {
+    Serial.println("Motor1 stall callback triggered - stopping motor!");
+    motor1.stop();
+}
+
+// Called when motor 2 stall is detected
+void onMotor2Stall() {
+    Serial.println("Motor2 stall callback triggered - stopping motor!");
+    motor2.stop();
 }
 
 void setupWiFi() {
@@ -44,13 +50,16 @@ void setup() {
     delay(1000);
     
     Serial.println("\n=============================");
-    Serial.println("  BTS7960 Motor Controller");
-    Serial.println("  Simple Stall Detection");
+    Serial.println("  Dual BTS7960 Motor Controller");
+    Serial.println("  Differential Drive Robot");
     Serial.println("=============================\n");
     
-    // Initialize motor controller
-    motor.begin();
-    motor.setStallCallback(onMotorStall);
+    // Initialize motor controllers
+    motor1.begin();
+    motor1.setStallCallback(onMotor1Stall);
+    
+    motor2.begin();
+    motor2.setStallCallback(onMotor2Stall);
     
     // Connect to WiFi
     setupWiFi();
@@ -65,6 +74,7 @@ void setup() {
 
 void loop() {
     handleWebServer();
-    motor.update();  // Update current sensing and logging
+    motor1.update();  // Update current sensing and logging for motor 1
+    motor2.update();  // Update current sensing and logging for motor 2
     delay(1);
 }