Function migrate_qdrant_collection_to_v3 

pub async fn migrate_qdrant_collection_to_v3(
    client: &Client,
    base_url: &str,
    collection: &str,
    api_key: Option<&str>,
) -> Result<usize>

Migrate a Qdrant collection to the V3 multi-agent shape.

Scrolls the collection in pages of 1000 points; for any point whose payload lacks agent_id, issues a set payload to add agent_id = "default". Idempotent: subsequent runs skip points that already carry the field.

Backups are the operator’s responsibility (documented in the release notes); we cannot snapshot a remote Qdrant cluster from inside the binary.