✨ Set up Copilot instructions and EditorConfig

[Copilot]

This PR configures GitHub Copilot instructions for the repository following best practices to help maintain code quality and consistency.

Changes

New Configuration Files

.editorconfig

• Standardizes code formatting across the repository
• Defines 2-space indentation for Bash, Markdown, JSON, YAML, and JavaScript files
• Enforces Unix line endings (LF) for cross-platform compatibility
• Disables max line length for Markdown (to accommodate tables and code blocks)

.github/instructions/general.instructions.md

• Provides general project context and guidelines for all files (**/*)
• Documents core principles: minimal dependencies, cross-platform compatibility, backward compatibility, and safety
• Includes development guidelines for code changes, documentation, and testing
• Describes file organization and common tasks

.github/instructions/README.md

• Documents the instruction system for future maintainers
• Explains each instruction file's purpose and scope
• Describes how the applyTo pattern system works
• Provides maintenance guidelines and external references

Existing Files Verified

The repository already had two excellent instruction files that were verified as part of this setup:

• .github/instructions/m.instructions.md - Comprehensive Bash script guidelines for bin/m
• .github/instructions/docs.instructions.md - Documentation-specific guidelines for Markdown files

How It Works

When GitHub Copilot or other AI coding assistants work on files in this repository, they automatically read and apply the relevant instructions based on the applyTo glob patterns in each instruction file's YAML frontmatter:

• **/* → General instructions apply to all files
• bin/m → Bash script-specific instructions
• /**/*.md → Documentation-specific instructions

This ensures AI-assisted changes maintain consistency with established patterns, follow safety practices, and preserve code quality.

Benefits

✅ Consistency - All changes follow established coding patterns and style
✅ Safety - Critical checks and validations are not bypassed
✅ Quality - Code reviews catch common issues automatically
✅ Context - AI assistants have necessary background about the project
✅ Documentation - Clear guidelines for both humans and AI

References

• Best practices for Copilot coding agent in your repository
• EditorConfig Specification

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• downloads.mongodb.org
  • Triggering command: curl -sSLf REDACTED (dns block)
• fastdl.mongodb.org
  • Triggering command: curl -Is REDACTED (dns block)
• https://api.github.com/repos/mongodb/mongo-tools/git/refs/tags
  • Triggering command: curl -sSf -H Accept: application/vnd.github.v3+json REDACTED (http block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

---

This section details on the original issue you should resolve

<issue_title>✨ Set up Copilot instructions</issue_title>
<issue_description>Configure instructions for this repository as documented in Best practices for Copilot coding agent in your repository.

</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes ✨ Set up Copilot instructions #162

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