feat: update Beast mode to v3.1

[martin-cod]

Pull Request Checklist

• I have read and followed the CONTRIBUTING.md guidelines.
• My contribution adds a new instruction, prompt, or chat mode file in the correct directory.
• The file follows the required naming convention.
• The content is clearly structured and follows the example format.
• I have tested my instructions, prompt, or chat mode with GitHub Copilot.
• I have run npm start and verified that README.md is up to date.

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Description

An update (v3.1) to well known Beast mode for GPT4.1 by Burke Holland. Source is here

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Type of Contribution

• New instruction file.
• New prompt file.
• New chat mode file.
• New collection file.
• Update to existing instruction, prompt, chat mode, or collection.
• Other (please specify):

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Additional Notes

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By submitting this pull request, I confirm that my contribution abides by the Code of Conduct and will be licensed under the MIT License.

[Copilot]

Pull Request Overview

This PR updates the "Beast Mode" chat mode from version 1.102 to version 3.1, incorporating improvements to the agent's workflow, communication guidelines, and new capabilities including memory management, environment variable handling, and git operations.

Key Changes

• Enhanced workflow instructions with more detailed research and debugging guidelines
• Added new sections for memory management, prompt writing, and git operations
• Updated formatting requirements for todo lists and communication patterns

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
docs/README.chatmodes.md	Updated the display title to reflect version 3.1 instead of VS Code v1.102
chatmodes/4.1-Beast.chatmode.md	Updated chat mode title and added extensive new instructions for memory, environment variables, prompt writing, and git operations

[martin-cod]

@burkeholland @jamesmontemagno coould you review it?