Hello, FreeRTOS

Your first RTOS challenge! Create two FreeRTOS tasks that take turns printing to the UART.

Task A should print "TASK_A" and Task B should print "TASK_B", each followed by a newline. Both tasks run at the same priority and use vTaskDelay() to yield to each other.

Order matters: the run must show two full A-then-B rounds — four task lines alternating, starting with Task A — followed by a final DONE line.

The simulation runs for 500 ms of virtual time, and all required output must appear within that window.