-- Which expiry reminders have gone out (docs/prd-point-coin.md F12): one per
-- customer, currency and expiry day. The row is written before the push is sent, so
-- several instances of the job, or a restart, never remind twice.
CREATE TABLE wallet_expiry_reminders (
    customer_id UUID NOT NULL REFERENCES customers(id) ON DELETE CASCADE,
    currency VARCHAR(10) NOT NULL CHECK (currency IN ('POINT','COIN')),
    expiry_date DATE NOT NULL,
    amount BIGINT NOT NULL,
    created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
    PRIMARY KEY (customer_id, currency, expiry_date)
);