Follow Member
Follow a member (idempotent — re-follow returns the original row, 201).
Bodyless POST. Runs the full visibility gate on the TARGET (contact_id) before attempting the follow — a blocked, hidden, banned, left, or missing target yields the gate’s own 403/404 with no existence leak.
load_visible_member’s READ gate deliberately lets an ELEVATED viewer (owner/admin/moderator) open a banned/soft_banned target and bypass hide_profile — correct for moderation reads, wrong for creating a follow edge. The write-specific re-check below applies to every viewer, elevated included, so a moderator cannot follow a banned or hidden member. It returns the exact same 404 shape the visibility gate uses so elevated and non-elevated responses stay indistinguishable (no new oracle for probing target state).
Authorizations
Bearer authentication header of the form Bearer <token>, where <token> is your auth token.