Record a conversation into an agent's memory of a contact

Teach an agent what was said, so the next call is not the first one.

This is how a conversation that happened somewhere ELSE - your own product, a human rep, another channel - becomes context the agent has. Calls the agent places itself are recorded already; this route exists for everything it did not witness.

Written to two places by voice: a durable interaction row and the vector memory retrieval reads. There is no delete for a memory on this surface.

The agent is named in the PATH for a readable URL. Voice's own handler scopes the write by (org_id, contact_id), so the memory attaches to the contact within the caller's org either way.