feat(resource-detail): add file size and mime type to document links

[SerdarAydemir]

What

Document download links now show the file size next to the type, e.g.
Title (PDF, 4,3 MB), with Dutch number notation. Builds on #1674 (Part 1).

After

The bottom document was uploaded after this change and shows the size;
the documents above it predate the change and gracefully fall back to
(PDF) — existing documents keep working unchanged.

Why

Relates to #1669 (Part 2). Part 1 added accessible humanized labels and the
file type. This part adds the file size, which WCAG 2.1 SC 2.4.4 calls for so
users know what they're downloading before they open it.

How — the size flows end-to-end

Tracing the upload chain, the size was being dropped at several points; this
PR fixes each:

1. image-server (/document, /documents): the upload response now
   includes size (bytes) and mimeType, which multer already provides.
2. admin document-uploader: forwards size/mimeType from the upload
   response to the form (previously only url/name).
3. admin resource-form: the zod schema for documents now accepts
   size/mimeType — zod strips unknown keys on submit, so without this the
   size never reached the API.
4. resource-detail widget: formatDocumentLabel takes the size and
   renders (PDF, 4,3 MB), with kB/MB formatting and a no-size fallback.

The documents field on the resource is a schemaless JSON column, so no
migration is needed.

Testing

• Component tests cover the label formatting (MB/kB, Dutch comma, no-size
  fallback) — 11 cases.
• Verified end-to-end locally: uploaded a PDF via the admin panel and
  confirmed size/mimeType are stored and rendered (see screenshot).

Notes

• Existing documents have no stored size and show (PDF) — this is the
  intended graceful fallback per Accessible document download links: display name, file type and file size #1669, not a regression. A backfill of
  existing documents could be a future improvement.
• No styling changes in the widget; label text only.

[SerdarAydemir]

Heads-up: the Docker build check is failing on denied: installation not allowed to Write organization package when pushing to ghcr.io. This looks like a registry-write permission issue for PRs from forks, not something in the diff — the Prettier and other checks pass. Let me know if there's anything I should change on my side.

[cypress]

Openstad Headless    Run #1893

Run Properties:   Passed #1893  •  df4d086277: feat(resource-detail): add file size and mime type to document links (#1691)

Project	Openstad Headless
Branch Review	main
Run status	Passed #1893
Run duration	33m 19s
Commit	df4d086277: feat(resource-detail): add file size and mime type to document links (#1691)
Committer	Serdar Aydemir
View all properties for this run ↗︎

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Test results
Failures	0
Flaky	0
Pending	0
Skipped	0
Passing	104
View all changes introduced in this branch ↗︎