Duplicate logs: `saving` is React state (async), so a burst of Enter presses /
clicks fired before the re-render each ran a full AddQSO and logged the same
QSO several times when a slow lookup made logging take a moment. A synchronous
savingRef guard now ignores the repeat immediately.
ESC: clearing the entry (ESC) left the "looking up" spinner turning and let a
still in-flight lookup re-populate the field afterwards. resetEntry now cancels
the pending lookup debounce, hides the spinner at once, and bumps a generation
counter so a late lookup result is discarded instead of applied.