Function record_segment_indexed 

pub async fn record_segment_indexed(
    pool: &SqlitePool,
    camera_id: &str,
    last_segment_at: DateTime<Utc>,
    bitrate_kbps: Option<f64>,
    fps_observed: Option<f64>,
) -> Result<()>

Record that a new segment was indexed: bump count, set last_segment_at and observed bitrate.