[Feature] Implement SAPO algorithm as an alternative to hard clipping in GRPO/GSPO

[romannekrasovaillm]

Do you have any plans to add support for Soft Adaptive Policy Optimization (SAPO) - the new RL algorithm that replaces hard clipping with smooth, temperature-controlled gating - to the slime framework?

[sam571128]

Looks like it's very simple to implement. You can use the same logic as GRPO but only change the clipping part. You can look into ppo_utils.py in the function compute_policy_loss().