✨ Set up Copilot instructions

[Copilot]

Configure instructions for this repository as documented in Best practices for Copilot coding agent in your repository.

Changes Made

Created .github/copilot-instructions.md with comprehensive guidelines for GitHub Copilot when working with the loda-cpp repository, including:

• Project Overview: Description of LODA language and this C++ implementation
• Architecture: Detailed breakdown of all source modules (base, cmd, eval, form, lang, math, mine, seq, oeis, sys)
• Building and Testing: Commands for all supported platforms (Linux x86/ARM64, MacOS x86/ARM64, Windows)
• Code Style Guidelines: C++17 standards, naming conventions, and formatting rules
• Key Concepts: Explanation of programs, sequences, mining process, and evaluation modes
• Common Tasks: Step-by-step guides for adding commands, generators, and tests
• Dependencies: List of required tools and optional dependencies
• Important Files: Key documentation and configuration files
• Guidelines for Changes: Best practices for contributing to the codebase

This will help GitHub Copilot provide better, more contextually appropriate suggestions when working on this repository.

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 #467

---

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.

[ckrause]

@copilot Can you prepare an initial version of the instructions?

[ckrause]

@copilot Can you prepare an initial version of the instructions?

[ckrause]

@copilot Can you prepare an initial version of the instructions?

[Copilot]

@copilot Can you prepare an initial version of the instructions?

Created initial Copilot instructions in .github/copilot-instructions.md. The file includes:

• Project overview and architecture
• Build/test commands for all platforms
• Code style guidelines
• Key concepts (programs, sequences, mining)
• Common development tasks
• Dependencies and important files

Commit: acd1955