PlanForm grew to seven fields with the billing rework, three of them
short day counts, and the modal ran off the bottom of the screen.
_modal_form.html gains two optional knobs -- box_class to widen the
box, two_columns to grid the fields -- so only the plan create/edit
modals opt in and every other modal renders exactly as before.
Textareas and file inputs still span the full width; below `sm` it
stays single-column, since two columns of form fields on a phone is
worse than a long scroll.
PlanForm's field order is chosen to suit that grid: pairing name with
duration and the two day-counts with each other fills every row
rather than leaving half of one empty next to the full-width
description.
Rebuilt static/css/app.css (unminified, matching how it is committed)
to pick up the new grid utilities.
Bernard Siebens
c2a4380b70