'top' and 'bottom' are positions relative to the input row, not the alt
screen viewport:
- top (default) → inline above the input, where the bar originally lived
(what 'on' used to mean)
- bottom → below the input, pinned to the last row
- off → hidden
Drops the literal top-of-screen placement; 'on' is kept as a backward-
compat alias that resolves to 'top' at both the config layer
(normalizeStatusBar, _coerce_statusbar) and the slash command.
ea32364c96