Adds a visually-hidden skip-to-content link as the first focusable
element. Adds id='main-content' to the <main> element. Changes
<section> to <main> on auth pages for proper landmark navigation.
Fixes WCAG 2.4.1 (Bypass Blocks).
CI shard 4 hit a ~996ms skew between the JS-constructed originalDue and
the backend's advanced due date, enough to bust the <500ms precision
bound. Bump precision to -4 (<5s) — still tight enough to confirm the
regeneration advanced by ~1 day, loose enough to absorb sub-second
round-tripping through Date → ISO → Go time.Time → JSON.
Keeps the Do* helpers framework-neutral so non-Echo callers (upcoming
Huma /v2 handlers) don't need a translation shim.
Addresses review feedback on #2670.
The Bulma form/checkbox-radio partial only defined two selectors: .checkbox
(consumed exclusively by FormCheckbox.vue) and .radio (consumed by
ViewEditForm.vue and user/settings/Avatar.vue). Ports the %checkbox-radio
placeholder rules (cursor, line-height, position, hover/disabled states,
and the input cursor override) into FormCheckbox's scoped style for the
.checkbox side, and into scoped style blocks on the two remaining .radio
call-sites for the .radio side (including the 0.5em sibling margin via
margin-inline-start). Drops the now-unused @import. Pixel-perfect verified
on /login, /user/settings/general, and /user/settings/avatar: every
measured label/input getBoundingClientRect and computed style matches the
baseline exactly (0px deltas across all 5 sampled checkboxes and all 5
avatar radios).
GuardLastAdmin counted only active, non-deletion-scheduled admins, but gated only on target.IsAdmin. Demoting or deleting an already-disabled or deletion-scheduled admin would then be blocked whenever exactly one active admin remained, even though removing a user who isn't in the reachable set can't reduce the count. Return early when the target isn't part of the counted set.