DLR-RM/stable-baselines3: v2.7.1: Bug fixes and documentation improvements

[!WARNING] Stable-Baselines3 (SB3) v2.7.1 will be the last one supporting Python 3.9 (end of life in October 2025) We highly recommended you to upgrade to Python >= 3.10. SB3 Contrib (more algorithms): https://github.com/Stable-Baselines-Team/stable-baselines3-contrib RL Zoo3 (training framework): https://github.com/DLR-RM/rl-baselines3-zoo Stable-Baselines Jax (SBX): https://github.com/araffin/sbx To upgrade: pip install stable_baselines3 sb3_contrib rl_zoo3 --upgrade New Features: RolloutBuffer and DictRolloutBuffer now uses the actual observation / action space dtype (instead of float32), this should save memory (@Trenza1ore) Bug Fixes: Fixed env checker to properly handle Sequence observation spaces when nested inside composite spaces (Dict, Tuple, OneOf) (@copilot) Update env checker to warn users when using Graph space (@dhruvmalik007). Fixed memory leak in VecVideoRecorder where recorded_frames stayed in memory due to reference in the moviepy clip (@copilot) Remove double space in StopTrainingOnRewardThreshold callback message (@sea-bass) SB3-Contrib Fixed tensorboard log name for MaskablePPO RL Zoo SBX (SB3 + Jax) Added CnnPolicy to PPO Documentation: Added plotting documentation and examples Added documentation clarifying gSDE (Generalized State-Dependent Exploration) inference behavior for PPO, SAC, and A2C algorithms Documented Atari wrapper reset behavior where env.reset() may perform a no-op step instead of truly resetting when terminal_on_life_loss=True (default), and how to avoid this behavior by setting terminal_on_life_loss=False Clarified comment in _sample_action() method to better explain action scaling behavior for off-policy algorithms (@copilot) Added sb3-plus to projects page Added example usage of ONNX JS Updated link to paper of community project DeepNetSlice (@AlexPasqua) Added example usage of Tensorflow JS Included exact versions in ONNX JS and example project Made step 2 (pip install) of CONTRIBUTING.md more robust New Contributors @Copilot made their first contribution in https://github.com/DLR-RM/stable-baselines3/pull/2167 @dhruvmalik007 made their first contribution in https://github.com/DLR-RM/stable-baselines3/pull/2139 @sea-bass made their first contribution in https://github.com/DLR-RM/stable-baselines3/pull/2179 @yongjincho made their first contribution in https://github.com/DLR-RM/stable-baselines3/pull/2181 @JonathanColetti made their first contribution in https://github.com/DLR-RM/stable-baselines3/pull/2183 Full Changelog: https://github.com/DLR-RM/stable-baselines3/compare/v2.7.0...v2.7.1