fix(config): report an out-of-range message_zoom

The documented 0.5 to 3.0 range was already enforced, by
MessageView::clampZoom(), so message_zoom = 500 rendered at 3.0 rather
than unusably. What was missing is the report: the key parses, so
nothing ever told the user that the value in their file is not the value
on screen.

Reported rather than clamped a second time. MessageView owns the bounds
and does the work; a copy of the range in Config would be free to drift
from the one that matters, so config.cpp reports against kMinZoom and
kMaxZoom directly. This is where it differs from toolbar_icon_size,
which has no widget-side enforcement to defer to.

Backlog item 58, whose recorded cause was wrong on this point and has
been corrected in place.

0 files changed, 0 insertions, 0 deletions