Add GitHub Copilot instructions for repository conventions

[Copilot]

Configures .github/copilot-instructions.md to provide Copilot with repository-specific context following best practices.

Contents

• Build/Test Commands: dotnet restore, dotnet build, dotnet test, dotnet format with framework-specific flags
• Project Structure: Maps src/tests directories to their purposes (NuGetLicenseCore, NuGetLicenseFramework, FileLicenseMatcher, etc.)
• Coding Conventions:
  • C# style from .editorconfig (Allman braces, 4-space indent, no var for built-in types)
  • Naming: _camelCase for private fields, s_camelCase for static fields (note: ported SPDX code uses UPPER_CASE)
  • Required license header for all C# files
• Multi-targeting: Targets net8.0, net9.0, net10.0, and net472 with cross-platform considerations
• Project-specific patterns: Reads from project.assets.json (not package restore), supports Table/Markdown/JSON output formats

SDK requirement clarified as 10.0.102+ (per global.json with rollForward).

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:

• gh.io
  • Triggering command: /home/REDACTED/work/_temp/ghcca-node/node/bin/node /home/REDACTED/work/_temp/ghcca-node/node/bin/node --enable-source-maps /home/REDACTED/work/_temp/copilot-developer-action-main/dist/index.js (dns 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 #389

---

💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud