Build a capped retry schedule

Implement retry_delays(attempts, base_ms, cap_ms).

Return one delay per retry attempt. The first delay is base_ms; each following delay doubles until cap_ms. Cap every delay, including the first. attempts is a non-negative integer; base_ms and cap_ms are positive integers. This deterministic exercise omits jitter.

Before coding, predict one result by hand. After the tests pass, explain your approach and add a boundary example of your own.