The Mastodon connector's uploadAll resolves asset ids via loadAsset/openAsset.
The registry wires these hooks from a mediaResolver that the scheduler injects:
media_assets lookup (workspace-scoped via SET LOCAL) + R2 download + SPENC1
decrypt (extracted from the api's storage into connector-runtime/media.ts).
provider-fetch gains serializeBody for multipart media uploads through the
pinned transport channel.
