feat(sim): record and replay MuJoCo state

[juelg]

• add a SimStateObservationWrapper that injects the full MuJoCo integration state into sim observations
• add replay utilities and a CLI/script to load recorded parquet trajectories and restore sim state step by step
• use duckdb as the preferred parquet reader, with a pyarrow fallback in library calls
• add a focused test that records sim state, reloads it from parquet, restores the sim, and re-renders a frame

Fixes #252.

[juelg]

this pr still relies on the old gym.make for the creation of the replay env and should use the new env config. This is tracked by #291