Drops the prev-sort snapshot ref. Diff is always available — no "sort once
first" empty state — and surfaces drops (banned/missing/collection IDs that
expanded), additions (collection expansion, branch picks), and reorderings
in one pass.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Add/remove/swap warning-action handlers no longer auto-fire /api/sort.
They mutate the input textarea idempotently; the sort button gets a
pending cue when current input != last-sorted input. Branch-picker
(/api/resort, cheap) keeps instant behavior. Spec lives in
docs/specs/2026-05-04-staged-warning-actions.md.
