fix: update muon implementation in optimizer and adjust parameter grouping

fix: correct flash-attn version in project dependencies and update authors format

Implement code changes to enhance functionality and improve performance

Merge pull request #19 from minpeter/feat/resume-checkpoint-support

Update src/krill/utils/resume.py

refactor: improve error handling in checkpoint validation functions

Merge branch 'feat/resume-checkpoint-support' of https://github.com/minpeter/krill into feat/resume-checkpoint-support

refactor: improve error handling for remote checkpoint validation and retrieval

Update src/krill/utils/resume.py

Update src/krill/utils/resume.py

Update src/krill/utils/resume.py

refactor: improve comments and error handling in text processing functions

feat: add comprehensive testing suite for resume functionality, including unit and integration tests

refactor: update resume checkpoint handling to use HF cache method

refactor: replace temporary checkpoint download with HF cache method