Commit ce5d6507cb

web: line the accounts row's controls up in columns

The disabled Promote loses its confirm field. It was there to keep the
cell's shape, but with the clipping gone both fields showed at once and
a pending row read as two identical "type <name> to confirm" boxes, one
of them inert. Dropping it is what the shape argument wanted anyway:
active and pending rows are now the same three controls in the same
places.

The cell is two fixed slots, each a field, a gap and a button wide, with
contents right-aligned. Sizing the slot rather than the form is what
holds the columns: the role button, the access field and the access
button each land on one rule whichever controls a row carries, and no
element stands in for the ones it does not. A form cannot span table
cells, so giving each control its own column and letting the table align
them needs form="" plumbing; this gets there without it.

Right-aligning the cell alone was not enough — the enable form has no
confirm field, so the disabled row's Promote sat where every other row
keeps its field. Two more things the generic form.actions rule did here:
it grew the button to fill the form, which ate the slot, and it wrapped,
which put the button on a line under the field. Both are overridden, and
the button takes a set width so the slot's arithmetic is exact.

The field goes 11rem to 14rem, which fits "type <name> to confirm" for
every account on the instance; the widest needs 176px of 190px. A long
enough name still truncates and the aria-label carries the instruction
in full either way.

Ref #247