CREATE TABLE IF NOT EXISTS room_attachment (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    message UUID NOT NULL,
    seq BIGINT NOT NULL,
    file_name TEXT NOT NULL,
    content_type TEXT,
    size_bytes BIGINT NOT NULL DEFAULT 0,
    storage_key TEXT NOT NULL,
    url TEXT,
    uploaded_by UUID NOT NULL,
    created_at TIMESTAMPTZ NOT NULL DEFAULT now()
);