Studio: show "Ended (collection rule)" on entries past an expiry gate (RFC-0042 §3.3) #113

RFC-0042 §3.3 (accepted, ADR-0044) asks Studio to show an entry whose collection's expiry rule has passed as Ended (collection rule), distinct from its own availability end. #107 left this out.

Today a published event past its expiry looks plainly published in Studio's list and editor, while the site has unlisted it (unlist) or answers 404 (hide). That mismatch is confusing.

Scope:

• A status badge in the collection list and the editor header, computed with derivedGate / entryVisibility from @cloudhal/core-ts/fields (already Worker-safe, Intl only).
• A tooltip naming the field, the action and the instant.
• Strings go in the listings namespace.
• No contract or API change.

Done when: an entry past its derived gate shows the badge in the list and editor, and tests cover the unlist, hide and not-yet-ended cases.