fix(provider-met): search through the paginated v1.1 endpoint

[MyPrototypeWhat]

The Met retired GET /public/collection/v1/search on 2026-10-01. It now answers 410 Gone, so every Met search failed. The weekly live-smoke run on 2026-10-05 caught it as met search failed: 410.

Change

• Search goes to /public/collection/v1.1/search. According to the Met's migration notes, it accepts every v1 filter unchanged and keeps the { total, objectIDs } shape. It adds offset and limit and returns one page of IDs.
• The provider asks for exactly the page it needs. offset comes from the requested page, and limit is the per-search object count, capped at 30 as before. Previously it downloaded every matching ID and sliced a window out of it. Keeping that slice on top of offset would have made every page after the first come back empty, and a test now pins this.
• Object records still come from /v1/objects/{id}, which is unchanged. All providerOptions filters are forwarded as before.
• Patch changeset for @refkit/provider-met.

Upstream behaviour checked live

• Consecutive pages are consistent: offset=0&limit=3 followed by offset=3&limit=3 returns the same IDs as offset=0&limit=6.
• No match, or an offset past total, returns objectIDs: null with status 200. The existing empty-result path handles it.
• limit above 500 is capped, and offset + limit is truncated at 10,000 without an error. The provider asks for at most 30 per page.

Testing

• Three new unit tests:

  • The search goes to v1.1 with offset/limit, and objects come from v1.
  • Page 3 sends offset=4/limit=2 and maps every ID the page returns.
  • Object fetches stay bounded to one page.

  The first two failed on main and pass now.

• REFKIT_LIVE=1 Met live smoke passes against the real API.

• Full gate: pnpm typecheck, pnpm lint, pnpm build, pnpm test:run (519 passed, 23 skipped), pnpm smoke:artifact.

Note: the Met often returns few usable results for a query. Many hits are copyrighted works whose images the Met does not release, and the provider drops those as before. For example, on the first two 4-ID pages for "lighthouse", only one object is public-domain with an image. This is unchanged by this PR.