Builds a day-by-day jet lag plan from flight times and your usual sleep hours. Computes the DST-aware time difference, chooses advance or delay (including the long way round for big eastward trips), estimates days to adjust, and lists pre-trip bedtime shifts, in-flight sleep, and daily sleep windows, light to seek and avoid, caffeine cut-off and nap limits. Flags short trips. Includes a stdlib Python planner with --self-test.
