MediaAttacher had grown into a 180-line class with four private
methods doing different things — download, validation, storage,
and post-state mutation. Two of those (lock-and-merge into the
JSON media column, intersection of allowed media types per
platform) are post concerns, not network concerns.
Move them onto the Post model:
Post::allowedMediaTypes(): array<Type>
The intersection of media types accepted by every enabled
platform. Used to be inlined as MediaAttacher::allowedMediaTypesFor.
Post::appendMedia(array $items): void
Lock-then-merge into the post's media[] JSON column so
concurrent writers don't overwrite each other. Used to be
MediaAttacher::mergeIntoPostMedia.
MediaAttacher now reads cleanly:
attachFromUrls — orchestrate (loop URLs, batch the appendMedia)
attachOne — download → validate type/size → handoff
download — Http::sink + progress abort, returns DTO
Drops to ~120 lines with no nested concerns. The streaming progress
abort uses the same throw-RuntimeException pattern, but now
contained in download() instead of leaking into the orchestrator.
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