feat(client): batch read methods for signed URLs, versions, metadata and folders

[ABujalance]

Summary

Client methods for the new storage batch endpoints. Pairs with platform_backend-api#352, which has the background: throttling is per endpoint per user, so a client that resolves one id per request runs into 429s well before it is doing anything abusive. Tile-based viewers and the models list panel both hit that today.

Changes

New methods on EngineServicesClient:

• getHiddenFileSignedUrlsBatch(hiddenIds, expiresIn?) — the one splat and point-cloud viewers should use instead of getHiddenFileSignedUrl per tile.
• listVersionsBatch(itemIds, { archived? }) — the returned records carry their metadata, so a list that only needs metadata does not need a second call.
• getFileVersionMetadataBatch(entries, { withDraft? }) — { itemId, versionTag } pairs.
• getFoldersBatch(folderIds) — for a known set of ids; listFolders({ projectId }) still covers the whole tree.

Shared behaviour:

• Inputs longer than STORAGE_BATCH_MAX (100) are split into several requests automatically, so callers never have to think about the ceiling.
• Entries come back in request order; an id the caller cannot read carries an error instead of data.
• An empty input returns [] without touching the network.

Also adds src/types/batch.ts (mirrors the backend types), a batch-reads.ts example, and a changeset.

Related

• platform_backend-api#352 — the endpoints. This needs those deployed before the methods work.