fix(web): name the last name author sort and offer it where it was missing (#2805)

[francisrath]

Summary

The Authors list already sorts by last name by default, but its menu said only "A–Z" next to "First name A–Z", so it read as if last name ordering were missing. This names it, and offers last name ordering in the two places that didn't have it, as proposed in #2805.

Closes #2805.

What changes

Where	Change
Authors sort menu	authors.sortAZ/ZA read "Last name A–Z / Z–A". Strings only; the sort is unchanged (sort_key, sort_name, where sort_name is "Last, First")
Merge authors dialog	Sorted by sortName, falling back to authorName for a row without one, with authorName as the tiebreaker, so it matches the page it opens from
Books grid sort menu	Adds Author A–Z / Z–A (author-az / author-za), which the server already accepted and only the table header reached

Translations are in a separate commit: the last name, first name and author sort labels in de, es, fr, nl, id, tl and ko. The first name pair was English-only in those locales, so their menus mixed languages. German, Spanish, French and Dutch are standard terms; Indonesian, Tagalog and Korean would benefit from a native reader. The nb and sv strings will be posted on #2994.

Checklist

• Every commit carries a Signed-off-by that matches its author (git commit -s)
• Changelog fragment added as changelog.d/2805-author-sort-names.md
• Tests added or updated
• No new dependency

Test plan

• cd web && npm run typecheck && npm test (1859 passed), eslint clean on the changed files
• Merge dialog test: authors listed by last name, a row without a sort name falls back to its display name
• Books page test: choosing Author Z–A in the grid sort menu requests sort=author-za
• All locale files parse; the i18n tests pass

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

📢 Thoughts on this report? Let us know!

[vavallee]

Thank you, this is a tidy fix and the issue writeup made it easy to check. Both new tests fail on main and pass here, and since useListParams already accepted the author sorts, a shared link with sort=author-za now shows the right option too. One tiny thing: the changelog fragment uses en dashes in the A to Z labels; could you write those out as "A to Z" and "Z to A"? Optionally, "Nom de famille" might read clearer than "Nom" in French. Happy to merge after that.

[francisrath]

Thanks! Done in 98efb395: "A to Z" / "Z to A" in the changelog, "Nom de famille" in French, and a test case with two authors sharing a sort name so the tiebreaker is covered (that was Codecov's two partials).