dev.cocore.account.friend

A one-way declaration that the publishing DID trusts the subject DID enough to route private (friends-only) compute jobs to them. Friending is *not* mutual and *not* a permission grant for the subject — it's the friender's own routing preference. The subject does not need to consent, sign anything, or even be aware. Published to the friender's PDS; multiple records for the same subject are tolerated (the rkey is `tid`) but the console deduplicates on upsert so steady state is one record per (friender, subject). The friends-only chat-completions endpoint reads these records to constrain the advisor's pickFor candidate set.