Constant NODE_DDL 

pub const NODE_DDL: &str = "
CREATE TABLE IF NOT EXISTS event_loop_lags (
    id              INTEGER PRIMARY KEY,
    session_id      TEXT NOT NULL REFERENCES sessions(id),
    lag_us          REAL NOT NULL,
    start_us        REAL,
    phase           TEXT,
    layer_id        INTEGER REFERENCES layers(id)
);
";

Node/JS-specific tables (event-loop lag).