ALTER TABLE mail_preferences ADD COLUMN flagged_on_top INTEGER NOT NULL DEFAULT 0;

CREATE TABLE IF NOT EXISTS folder_preferences (
    folder_name TEXT PRIMARY KEY REFERENCES folders(name) ON UPDATE CASCADE ON DELETE CASCADE,
    flagged_on_top INTEGER CHECK(flagged_on_top IN (0, 1) OR flagged_on_top IS NULL),
    updated_at TEXT NOT NULL DEFAULT (datetime('now'))
);