Frontend: mark the public version and open what a listing advertises

### Task Summary

Part of #7828, and the last task in the series. Two places outside the share dialog have to
agree with the pin.

- **The versions panel marks the version the Hub is serving**, as a quiet second line under its
timestamp — the panel is 230px wide, so horizontal room is scarce while vertical room is free.
That row is also how an author who has moved on gets the published copy back: it is already in
the panel, so restoring it is the restore they already know.
- **It re-reads when the share dialog closes**, since that is where the pin can have moved and
the panel is covered until then. The dialog announces the change rather than reaching down
into the panel, which keeps the dependency one-way.
- **A hub entry opens what it advertises.** A hub card shows the public copy, but clicking it
took the author into their editor, so the workflow they had just seen described one way opened
another. An author whose working copy has moved on behind a pin now lands on the published
preview — what they just saw, and where Clone gives them a copy of it.
- **Their own listings are untouched**: under Your Work the entry is their workflow, and it
opens the editor as before.

Covered by `versions-list.component.spec.ts`, `list-item.component.spec.ts`,
`card-item.component.spec.ts` and `menu.component.spec.ts`: the routing rule in both the list
and the card view, the panel showing the mark, re-reading when told to, and leaving unmarked
rows alone.

### Task Type

- [ ] Refactor / Cleanup
- [ ] DevOps / Deployment / CI
- [ ] Testing / QA
- [ ] Documentation
- [ ] Performance
- [x] Other