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

.vscode/extensions.json

@@ -0,0 +1,10 @@
+{
+    // See http://go.microsoft.com/fwlink/?LinkId=827846
+    // for the documentation about the extensions.json format
+    "recommendations": [
+        "platformio.platformio-ide"
+    ],
+    "unwantedRecommendations": [
+        "ms-vscode.cpptools-extension-pack"
+    ]
+}