Function seed_builtin_agents 

pub async fn seed_builtin_agents(
    persistence: &dyn PersistenceLayer,
) -> Result<()>

Seeds built-in agents into the persistence layer at startup.

The assistant and orchestrator are refreshed by idempotent upserts so system updates apply. Specialist defaults are inserted only when absent, preserving operator-registered artifacts under those names. Because agents are persisted, the realtime entity bus will re-emit them after any Agent ChangeSet, making them reliably visible in the admin list and chat selector without relying on the ensure_builtin_agent shim.

Call this alongside ensure_default_knowledge_base in server startup.