install.sh created the virtualenv with --system-site-packages so it could
see the pin backend, but never installed one. On a Pi OS image whose
python3-gpiozero does not pull it in, gpiozero then raised BadPinFactory,
the app fell back to a no-op LED, and the reader ran with the light dark
and nothing failing - the failure that is easiest to miss. Install
python3-lgpio (Bookworm and later) or python3-rpi.gpio (older releases)
when neither backend is importable, best-effort like the packages above.
Adds the installation and API guide (DOCX, 36 pages, 4 figures, 25
tables) covering enabling the serial port, wiring, mounting, installing on
Raspberry Pi OS and the complete HTTP API, plus the header diagrams it
references.
.gitignore now excludes the release build outputs: they are generated from
the source tree, and committing them would duplicate the code.
Co-authored-by: Copilot <[email protected]>
