End-to-end: resolves the agent's media kit (override > agent default) and returns the formatted
agent context note, or null when there is no kit / no showable items. Best-effort: logs and
returns null on any failure so it can never break session start.
End-to-end: resolves the agent's media kit (override > agent default) and returns the formatted agent context note, or
nullwhen there is no kit / no showable items. Best-effort: logs and returnsnullon any failure so it can never break session start.