refactor

[SeanLee97]

• use uv to manage dependencies
• simplify the implementation
• Remove all imports of AngleDataTokenizer
• Remove all imports of DatasetFormats
• Remove all .map(AngleDataTokenizer(...)) calls
• Update dataset field names (text → query for Format B/C) OR use --column_rename_mapping
• Add is_llm=True to LLM model initialization
• Replace --prompt_template with --text_prompt, --query_prompt, or --doc_prompt
• Update training scripts to use accelerate launch
• Update evaluation code if using the return value
• Support input data as a list of strings. New data formats:
  • A: {"text1": str | List[str], "text2": str | List[str], "label": float}
  • B: {"query": str | List[str], "positive": str | List[str]}
  • C: {"query": str | List[str], "positive": str | List[str], "negative": str | List[str]}
• Support fsdp training
• Update docs
• Test code with the new version
• migration guideline