v4.0.0

Upgrade guide: docs/migrations/4.0.0.md.

• feat!: Replace eslint-plugin-jsx-a11y with eslint-plugin-jsx-a11y-x, its maintained eslint-community fork with
  eslint 10 support. Rule IDs and the settings key move from jsx-a11y to jsx-a11y-x, so eslint-disable comments
  and rule overrides naming jsx-a11y/* must be renamed. The enabled rules, severities and options are unchanged.
• chore: Drop ~100 transitive packages (the polyfill tree eslint-plugin-jsx-a11y pulled in).
• feat!: Vendor @total-typescript/ts-reset as ts-reset.d.ts and drop the dependency; npm is stuck at 0.6.1 because
  upstream's 0.7.0 publish failed. reset.d.ts now carries 0.7.0's /dom set: .catch()/.then() on a
  Promise<A> | Promise<B> union compiles again (the reason parameter is any again), .filter(Boolean) inline in a
  call argument now type-checks its elements, and cloneNode() keeps the element type. 0.7.0's Map.groupBy/
  Object.groupBy overrides are left out, since they would make groupBy typecheck under the ES2022 lib.