List items used as tab panels are reported by aria-allowed-role even when their parent has no list semantics. This fixes the presentational list pattern in #4910 by allowing arbitrary roles only when the immediate represented parent is known not to have the list role.

Native and explicit list restrictions, presentation conflicts, role-token precedence, custom-element roles and unknown-parent behavior remain covered. Parent classification avoids accessible-name lookup, which can recurse through the child being checked. The patch adds matcher, standards, serialized-tree and HTML/JSON regressions, including shadow DOM cases.

Validation:

• Build, TypeScript, formatting, lint and the Node/jsdom test scripts pass.
• Eight new regressions fail on the original bundle and pass with the fix. The focused Chromium runs pass 167 unit/virtual tests and 19 rule-fixture assertions.
• All eight browser groups were attempted in local Chromium: 8,806 passed, 101 skipped. Five assertion failures and one existing fixture hook timeout blocking 134 assertions also reproduce against the original bundle. The failures concern selector generation, object loading, shadow ID references and target offsets.
• The full test command exits 1 after the first failing group; the remaining seven groups were run separately with continue-on-error. These runs use the original WTR assertions and timeouts with a local passive browser launcher and a content-hash bundle URL. No runner or existing test expectation changes are included. Stock Selenium and Firefox remain unverified.
• A broader selected jsdom run passes 469 tests with two fixture errors because setHTMLUnsafe is unavailable; those shadow cases pass in Chromium.

Closes: #4910