feat: implement slave handler and api

usage.py

@@ -0,0 +1,40 @@
+from i2c_handler import I2CSlaveHandler, Packet
+
+class MyRobotHandler(I2CSlaveHandler):
+    def process_packet(self, packet: Packet):
+        """
+        Example: Override process_packet to perform actions based on packet command/type.
+        """
+        cmd = packet[0]
+        target = packet[1]
+        speed = (packet[2] << 8) | packet[3]
+        # Convert speed from unsigned to signed if needed
+        if speed & 0x8000:
+            speed -= 0x10000
+
+        print(f"Custom handler: Command 0x{cmd:02X}, Target 0x{target:02X}, Speed {speed}")
+
+        # Example: Perform a motor action for command 0x01
+        if cmd == 0x01:  # Set Motor Speed
+            print(f"Setting motor {target} speed to {speed}")
+            # TODO: Add your motor control code here
+
+        elif cmd == 0xFF:  # Emergency Stop
+            print("Emergency stop received!")
+            # TODO: Add your emergency stop code here
+
+        else:
+            print("Unknown command")
+
+# Usage example
+def main():
+    handler = MyRobotHandler(i2c_id=0, sda=0, scl=1, slave_addr=0x41)
+    print("MyRobotHandler I2C slave started")
+    try:
+        handler.handle()
+    except KeyboardInterrupt:
+        handler.deinit()
+        print("I2C slave stopped")
+
+if __name__ == "__main__":
+    main()