chore: update .gitignore to include mise.toml and improve contributin…

[BenjaminX]

…g instructions

Summary

Update dev contributin guide

Tip

Close issue syntax: Fixes #<issue number> or Resolves #<issue number>, see documentation for more details.

Impact Areas

Please check the areas this PR affects:

• Multi-threaded Dialogues
• AI-Powered Capabilities (Web Search, Knowledge Base Search, Question Recommendations)
• Context Memory & References
• Knowledge Base Integration & RAG
• Quotes & Citations
• AI Document Editing & WYSIWYG
• Free-form Canvas Interface
• Other

Checklist

Important

Please review the checklist below before submitting your pull request.

• This change requires a documentation update, included: Refly Documentation
• I understand that this PR may be closed in case there was no previous discussion or issues. (This doesn't apply to typos!)
• I've added a test for each change that was introduced, and I tried as much as possible to make a single atomic change.
• I've updated the documentation accordingly.
• I ran dev/reformat(backend) and cd web && npx lint-staged(frontend) to appease the lint gods

[mrcfps]

Can you remove (just once) hint here (or add it to the comment)? The command won't run.