-- Backpack: unequipped gear (max 40 slots per hero).
CREATE TABLE IF NOT EXISTS hero_inventory (
    hero_id     BIGINT NOT NULL REFERENCES heroes(id) ON DELETE CASCADE,
    slot_index  SMALLINT NOT NULL CHECK (slot_index >= 0 AND slot_index < 40),
    gear_id     BIGINT NOT NULL REFERENCES gear(id) ON DELETE CASCADE,
    PRIMARY KEY (hero_id, slot_index),
    UNIQUE (gear_id)
);

CREATE INDEX IF NOT EXISTS idx_hero_inventory_hero ON hero_inventory(hero_id);