Set up GitHub Copilot coding agent instructions

[Copilot]

Adds .github/copilot-instructions.md to configure GitHub Copilot coding agent behavior for this repository, following the recommended best practices.

What's included

• .github/copilot-instructions.md — Comprehensive agent context covering:

  • Project purpose and 3-layer architecture (Wails App → Service → Convert package)
  • Data flow from frontend through auto-generated Wails bindings to Go backend
  • Development commands, test conventions (table-driven, 92% coverage), and build targets
  • Convert package design principles: flexible hex parsing, generic type constraints, endianness naming conventions, exported error types
  • Code style rules (gofmt, fmt.Errorf wrapping patterns)
  • Step-by-step guides for common tasks (adding conversions, updating UI, cross-platform builds)

• .github/prompts/ — Reusable prompt files for interactive prompt refinement (boost-prompt) and finalization (finalize) workflows

Original prompt

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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 #5

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⌨️ Start Copilot coding agent tasks without leaving your editor — available in VS Code, Visual Studio, JetBrains IDEs and Eclipse.