feat: add CAJAL scientific paper generator custom mode example

[roomote-v0]

This PR attempts to address Issue #12256.

Summary

Adds a ready-to-use .roomodes file and documentation for the CAJAL scientific paper generator mode, following the agreed-upon approach of starting with a distributable custom mode before considering a built-in mode.

What is included

• docs/community-modes/cajal-paper-generator/.roomodes -- A complete custom mode definition that users can copy into their project root to enable the Paper Generator mode
• docs/community-modes/cajal-paper-generator/README.md -- Documentation covering installation, usage, the tribunal workflow, and configuration options

How it works

The paper mode defines a structured workflow for generating scientific papers:

1. Pass 1 (Draft): Generates a 7-section paper (Abstract, Introduction, Related Work, Methodology, Results, Discussion, Conclusion) with real arXiv citations
2. Pass 2 (Tribunal): Simulates 3 independent reviewers scoring each section (0-10)
3. Pass 3 (Refinement): Rewrites sections scoring below 7, up to 3 iterations

The mode uses file restrictions to only write .md, .tex, .bib, .txt, .csv, and .json files, preventing accidental source code modifications.

No core code changes

This is purely additive documentation -- no changes to extension source code, tests, or configuration. The mode works through the existing custom modes system (.roomodes files) and requires zero new infrastructure.

Testing

• YAML parses correctly and validates against the .roomodes schema
• Existing CustomModesSettings and modes test suites pass (14 + 45 tests)
• All linting and type checks pass

Feedback and guidance are welcome.

Refs: #12256

Interactively review PR in Roo Code Cloud

[Agnuxo1]

Hi team! This PR is ready for human review. The .roomodes definition has been tested and validated.

Could a maintainer please:

1. Mark this PR as Ready for Review (remove Draft status)
2. Review the .roomodes schema and README
3. Consider adding to the community modes documentation

The CAJAL community is excited about this integration — it's a fully functional scientific paper generation mode that works out of the box with the existing Roo Code custom mode system.

Happy to address any feedback! 🙏

[Agnuxo1]

Hi @cte and Roo Code team! 👋

This PR has been in draft for ~14 hours now. The implementation is complete:

✅ .roomodes file with CAJAL paper generation mode
✅ Tribunal scoring system (3 reviewers, 0-10)
✅ Iterative rewrite logic
✅ Documentation included

Could you mark it as Ready for Review when you have a moment? Happy to address any feedback promptly.

Context: CAJAL is a local scientific paper generator with peer review that runs via Ollama. 50 papers evaluated, avg score 7.3/10.

Paper: https://arxiv.org/pdf/2604.19792
Repo: https://github.com/Agnuxo1/CAJAL

Thanks for maintaining Roo Code — it's an incredible tool!