Media metadata capabilities: how would you prefer these requests brought?

## Context

While building a metadata-driven media gallery on Grav 2.1 (a theme plus the API
plugin), I took the liberty of analysing where the media / `.meta.yaml`
capabilities tend to stop short of what a curator-facing gallery needs. I have a
few small, separately-scoped observations written up, and thought it best to ask
how you'd prefer to receive them before opening anything.

Grav 2.0 is API-first and already moved media in this direction: `.meta.yaml`
metafiles, media as a first-party API resource, upload and metadata editing in
Admin Next, and the metadata queries added to `page.media` in 2.0.11 (#4200).
These observations simply continue that path toward a full gallery experience.

Most of what I have is API-plugin side (listing, batching, filtering, field
types); a couple are core-side (metadata defaults, EXIF, a metadata write API).
Happy to file each wherever fits best.

## What I've been looking at

Briefly:

- batch metadata for page media (site media already has it);
- metadata included in media list responses, to save a per-file `/meta` call;
- grouping/facet output, and a `search` that composes with `filter`/`sort`;
- pagination for the page-media listing;
- a few more metadata field types (e.g. number, date, select);
- some extensibility and i18n points (registering metadata fields, custom field
types, translatable labels, and per-language values);

plus a couple of possible core-side items (folder-level metadata defaults, EXIF
re-extraction, a programmatic metadata write API).

## If you have a moment

- Would you prefer one issue per item, or an umbrella/tracking issue?
- Is any of this already planned, in progress, or intentionally out of scope?
- Is there a preferred order, or labels/milestones these should attach to?
- Anything above you'd rather I leave alone?

I'm glad to reshape, merge, or drop anything already covered — and I haven't
filed anything yet.

---

*This report was generated with AI assistance.*

Start with the API plugin's existing media resource, page-media listing, and /meta behavior described in the issue, then review the related media metadata work in Grav 2.0.11 (#4200). The listed observations need to be split into separately scoped proposals or an agreed tracking issue. Done means maintainers have chosen the scope, ownership, order, and whether each item is planned or out of scope.

Written by the indexing model from the issue text.