Checkpoints and reproducibility — step 6 of 7

Write run(seed, steps=5): create a PRIVATE random.Random(seed) generator, start w at 5.0, subtract 0.1 * rng.uniform(0.5, 1.5) each step, return w rounded to 6 places. Prove the reproducibility contract: same seed twice gives identical results, a different seed doesn't. Print the two checks and seed 42's value.