Constant MIGRATION_V37 

pub const MIGRATION_V37: &str = "\
CREATE TABLE IF NOT EXISTS mutation_journal (
    journal_id      INTEGER PRIMARY KEY AUTOINCREMENT,
    home_device_id  TEXT NOT NULL,
    store_id        TEXT NOT NULL,
    sequence        INTEGER NOT NULL,
    operation_kind  TEXT NOT NULL,
    payload         BLOB NOT NULL,
    created_at      TEXT NOT NULL DEFAULT (datetime('now'))
);
CREATE UNIQUE INDEX IF NOT EXISTS idx_journal_sequence
    ON mutation_journal(home_device_id, store_id, sequence);
";

V37 migration: mutation journal for device-owned replication.