FC06 — FreeRTOS software timers

This card distinguishes successful timer command submission from later command processing and callback execution by the timer daemon. The deterministic replay uses one one-shot timer and one auto-reload timer. It resets the one-shot before its original expiry and changes the auto-reload period after two callbacks.

Expected callback ticks are auto=[2,4,7] and one-shot=6. The callback runs on the daemon stack, obtains a typed TimerTag through pvTimerGetTimerID() and only records bounded evidence.

make check
python3 /home/user/dev/workspace/stem/tools/card-layouts/tools/build_freertos_c_card.py .
python3 /home/user/dev/workspace/stem/tools/card-layouts/tools/render_card.py .