chore: improve .gitattributes for cross-platform consistency

[TranscendenceLiang]

• Add text=auto for automatic text file detection
• Set explicit line endings for Python (LF), Shell (LF), Batch (CRLF)
• Mark binary files (images, fonts, archives) to prevent corruption
• Exclude third-party directories from diff computation

Description

[Describe what this PR does and why]

Related Issue: Fixes #(issue_number) or Relates to #(issue_number)

Security Considerations: [If applicable, e.g. channel auth, env/config handling]

Type of Change

• Bug fix
• New feature
• Breaking change
• Documentation
• Refactoring

Component(s) Affected

• Core / Backend (app, agents, config, providers, utils, local_models)
• Console (frontend web UI)
• Channels (DingTalk, Feishu, QQ, Discord, iMessage, etc.)
• Skills
• CLI
• Documentation (website)
• Tests
• CI/CD
• Scripts / Deploy

Checklist

• I ran pre-commit run --all-files locally and it passes
• If pre-commit auto-fixed files, I committed those changes and reran checks
• I ran tests locally (pytest or as relevant) and they pass
• Documentation updated (if needed)
• Ready for review

Testing

[How to test these changes]

Local Verification Evidence

pre-commit run --all-files
# paste summary result

pytest
# paste summary result

Additional Notes

[Optional: any other context]

[github-actions]

Welcome to CoPaw! 🐾

Hi @TranscendenceLiang, this is your 4th Pull Request.

🙌 Join Developer Community

Thanks so much for your contribution! We'd love to invite you to join the official CoPaw developer group! You can find the Discord and DingTalk group links under the "Developer Community" section on our docs page:
https://copaw.agentscope.io/docs/community

We truly appreciate your enthusiasm—and look forward to your future contributions! 😊

We'll review your PR soon.

[gemini-code-assist]

Code Review

This pull request updates the .gitattributes file to include comprehensive rules for line endings, binary file definitions, and exclusions for generated directories. The changes establish LF as the standard for shell scripts, Python, and web-related files while maintaining CRLF for Windows batch files. A review comment suggests further extending these rules to include other common text-based formats like JSON, Markdown, and YAML to ensure consistent behavior across all developer environments.