Function public_commit_outcome_on_conn 

pub fn public_commit_outcome_on_conn(
    conn: &Connection,
    transaction_id: &str,
    now_ms: i64,
    resolve_cursor: impl FnMut(&Connection, &str, &StoredPublicOutcome) -> Result<Option<String>, SessionError>,
) -> Result<Option<Option<String>>, SessionError>

Resolve the terminal outcome of a public transaction from committed metadata only.

Cursor recovery is the host seam: an HCTree producer scans/backfills its journal, while a standalone WAL2 host supplies a resolver that returns Ok(None) because its outcome cursor is co-transactional with the data commit. A retained row with a run id whose cursor cannot be resolved is expired; an absent row expires only at or below the transaction retention floor.