test: add interactive-roles util test + document progressbar divergence

Covers the full util surface:
- Canonical widget roles (button, link, combobox, etc.) — in set
- Composite-widget containers (listbox, grid, tablist, tree, treegrid) — in set
- toolbar manual override — in set (documented exception)
- tooltip exclusion — NOT in set (WAI-ARIA 1.2 §5.3.3)
- progressbar included (documented divergence from lit-a11y)
- Set-size pin (35 roles) — surfaces aria-query taxonomy drift as test failure
- COMPOSITE_WIDGET_CHILDREN sanity (listbox/option, grid/gridcell transitivity,
  treegrid/row+treeitem superClass inheritance, radiogroup/radio, submenu)

Also extend the util JSDoc to document progressbar inclusion vs lit-a11y's
readonly-value-based exclusion — previously only noted in the PR body.

Author: johanrd

lib/utils/interactive-roles.js

@@ -5,14 +5,25 @@ const { roles } = require('aria-query');
 // peer-plugin behavior here):
 //   https://github.com/jsx-eslint/eslint-plugin-jsx-a11y/blob/main/src/util/isInteractiveRole.js
 //
+// Authority: aria-query widget taxonomy, one manual addition, one manual
+// exclusion. Both documented below.
+//
 // `toolbar` is added explicitly — it does not descend from `widget` per
-// aria-query's taxonomy, but supports `aria-activedescendant` and is widget-
-// like in practice. jsx-a11y adds it for the same reason.
+// aria-query's taxonomy (its superClass is structure-based), but supports
+// `aria-activedescendant` and is widget-like in practice per WAI-ARIA APG's
+// toolbar pattern. jsx-a11y adds it for the same reason.
 //
 // `tooltip` is intentionally NOT added. Per WAI-ARIA 1.2 §5.3.3 — Document
 // Structure Roles (https://www.w3.org/TR/wai-aria-1.2/#tooltip), tooltip is
 // a document-structure role, not a widget; the spec says "document structures
 // are not usually interactive." jsx-a11y agrees.
+//
+// `progressbar` IS included (it descends from widget → range per aria-query).
+// lit-a11y explicitly excludes it on the grounds that `progressbar.value` is
+// always readonly, so the role isn't operable by the user. This is a real
+// design disagreement; we side with aria-query's taxonomy (and jsx-a11y) to
+// keep the authority single-sourced. Authors wanting lit-a11y behavior can
+// layer a rule-level exclusion if needed.
 module.exports.INTERACTIVE_ROLES = buildInteractiveRoleSet();
 
 // Composite-widget child map — for each composite-widget parent role, the