The COM port was a bare text field — the only serial device in the app without
a port list, and typing one by hand gave no clue when it failed.
A Combobox rather than the Select the other devices use, deliberately: the port
of a USB adapter that is not plugged in does not appear in any list, and
refusing a typed value would mean the antenna cannot be configured until the
adapter is in. Detected ports are offered, anything else is still accepted, and
the value is trimmed and upper-cased on the way in.
The failure itself was already logged by the SteppIR client ("cannot open COM7
@ 4800 baud"); what was missing was the line above it not claiming the antenna
had connected. That is fixed separately.
Carries the 0.26.2 changelog entries for this and the three preceding commits —
one file, and splitting it four ways would have said less than this does.