squint: draw the overlay for a page that changed height

A page that changed height is the commonest kind of visual change there
is, and Compare refused to draw anything at all when the two renderings
were different shapes -- so the one case you most want an overlay for was
the one case you never got one. Six shots moved on the last real check and
the diff directory was empty.

Both sides are measured against a canvas big enough for either now. A pixel
that exists in one rendering and not the other counts as changed, which is
true: a page that grew by two lines did move everything below them, and the
overlay shows exactly that -- untouched above the change, red from the
change down, and a solid band at the foot for the part that only exists
now. The verdict keeps the resize note and adds the count.

The skill also stops throwing the evidence away. It now says to leave
.squint/ in place: the user may ask to see the diffs as a final check, and
regenerating after the change is committed means comparing against HEAD~1
rather than HEAD. It explains how to read an overlay too, since the useful
signal on a resized page is the topmost red, not the large red area below
it that is only the shift.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01X1aAjLD4wvan3wsmkHPPh3

James Millscommitted 1 month agoparent c5251420782a55d2470bf1cc5e4db6d2a0d028c49b9c878Browse files