List connected accounts

The agent's account-discovery endpoint: id, platform, username, status per connected account. Each account also carries ref — the readable name to send in social_accounts when creating a post (x:someone). Use it rather than the id: an agent's post is shown to a person to approve, printed as the agent wrote it, and a uuid asks them to approve a destination they cannot see. ref is always sendable as returned; for the rare account whose username is duplicated on its platform it IS the id. Each account also carries limits and can — what this connection will actually publish. limits: caption_chars, caption_chars_available (the room the caption really has), max_media, media_required (a text-only post is refused where true), video_seconds. can: placements (surfaces beyond the feed), first_comment, people_tags, reel_music, documents, mixed_media. These are route facts, not the platform's brochure: Threads documents 20 attachments and takes 10 through us, Pinterest carousels five images on a natively connected account and pins one through the aggregator — max_media follows the route — and several of the can flags depend on how this account was connected.