Build and push server image / build-and-push (push) Successful in 37s
All firmware-related controls (manual upload, Gitea repo URL, auto-update checkbox, detected board, Update frame button) now live in one "Firmware update" card instead of being split across the main Settings form and a separate card. The board variant used to pick a Gitea release asset was a dropdown the user had to set by hand and could get wrong. The device now reports it itself via a new X-Frame-Board header (CONFIG_FRAME_BOARD_NAME, "devkit" by default, "xiao" in sdkconfig.xiao) on every /frame/config poll, stored as device_board_variant -- the server learns it instead. Update checks/applies are gated on the board being known, since there's nothing to fetch until a device has checked in at least once.