Add GitHub Copilot instructions for repository

[Copilot]

Configures .github/copilot-instructions.md to provide context-aware guidance for the repository.

Changes

• Project context: Overview of Plugin.ByteArrays as a .NET 9.0 library for byte array utilities with support for 60+ type conversions across byte[], ReadOnlySpan<byte>, and ReadOnlyMemory<byte>

• Development standards:

  • Code organization patterns (partial classes by category: ByteArrayExtensions.*.cs)
  • Naming conventions from .editorconfig (PascalCase types/methods, _camelCase private fields)
  • Method variants: ToType() throws, ToTypeOrDefault() returns default, ref position auto-advances
  • XML documentation requirements for all public APIs

• Testing patterns: xUnit with FluentAssertions, test naming MethodName_Scenario_ExpectedBehavior, 616+ tests covering success/failure paths and boundary conditions

• Performance guidance: Prefer ReadOnlySpan<byte> for zero-copy operations, use stackalloc for small buffers, avoid allocations in hot paths

• Common patterns vs anti-patterns:

  // ✅ Position tracking with auto-advance
  var position = 0;
  var id = buffer.ToInt32(ref position);      // position = 4
  var name = buffer.ToStringUtf8(ref position, 20); // position = 24
  
  // ❌ Manual slicing (inefficient)
  var subset = array.Skip(offset).Take(length).ToArray();
  var value = BitConverter.ToInt32(subset, 0);

• Commit message format: Conventional Commits guidelines with type, scope, and subject format (e.g., feat(extensions): add ToDecimal conversion method), including common types (feat, fix, docs, style, refactor, perf, test, chore) and formatting rules

• Build/test/CI: Commands for dotnet restore/build/test, GitHub Actions pipeline with versioning, NuGet publishing, and DocFX documentation deployment

• Dependencies: All packages from Directory.Packages.props including xUnit 2.9.3, FluentAssertions 7.2.0, .NET 9.0 SDK

• Fixes ✨ Set up Copilot instructions #13

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.

This repo is a dotnet project around byte arrays. I have enabled highest code quality checks, so the code needs to be crystal-perfect, tested and documented.</issue_description>

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

• Fixes ✨ Set up Copilot instructions #13

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💡 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.

[framinosona]

@copilot could you add also that this repo uses conventional commits format ?

[Copilot]

@copilot could you add also that this repo uses conventional commits format ?

Added conventional commits format guidelines in commit 2580ca7. The section includes:

• Commit message structure with type, scope, subject, body, and footer
• Common types (feat, fix, docs, style, refactor, perf, test, chore)
• Examples following the pattern used in this repository
• Guidelines for formatting (lowercase, imperative mood, character limits, breaking changes)

[Copilot]

Pull Request Overview

This PR adds comprehensive GitHub Copilot instructions for the Plugin.ByteArrays project. The document provides detailed guidance on project structure, coding standards, testing practices, and development workflows.

• Added a 395-line copilot-instructions.md file covering all aspects of the project
• Documented technology stack, dependencies, and CI/CD pipeline details
• Included coding standards, testing guidelines, and performance best practices

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💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[github-actions]

Test Results

616 tests  ±0   616 ✅ ±0   1s ⏱️ ±0s
  1 suites ±0     0 💤 ±0 
  1 files   ±0     0 ❌ ±0 

Results for commit 2580ca7. ± Comparison against base commit 5a52d18.