[DPO] Drop subprocess inference, add more framework support, doc update

[wheresmyhair]

Overview

Support more inference frameworks when doing DPO, trl version update, and readme update

Detailed Description

• iterative_dpo_aligner
  • Choose inference engine in-process - VLLMInferencer or SGLangInferencer based on inference_engine arg;
  • fix DataProto -> text_to_textlist conversion left misaligned by [Data] Apply DataProto to vLLM Inference & Align API with SGLang #967 (n>1 rollouts are repeat-interleaved by prepare_inputs_for_inference and need to be ungrouped via meta_info["actual_n_rollouts"]).
• vllm_inferencer
  • mark MemorySafeVLLMInferencer deprecated with DeprecationWarning;
  • scheduled for removal in lmflow 1.1.0.
• auto_pipeline
  • relax iterative_dpo_aligner gate from vllm AND trl AND ray to trl AND (vllm OR sglang);
  • ray is only needed for the opt-in distributed reward inference path, and will be removed in the future to achieve a ray-less pipeline.
• setup.py
  • bump trl 0.8.0 -> trl>=0.11,<0.12;
  • add pybase64 to [sglang] and rich to [trl] to work around upstream packaging gaps (sglang.utils eagerly imports pybase64; trl 0.11.x lazy-imports rich).
• README + 5 localized READMEs
  • document optional dependency extras and the vllm/sglang environment incompatibility.