Create Copilot instructions for Dio repository

[Copilot]

Added comprehensive .github/copilot-instructions.md file to onboard coding agents to the Dio repository efficiently. This file provides essential information about the codebase structure, build processes, and development workflows to minimize exploration time for future agent interactions.

What's included:

Repository Overview:

• Summary of Dio as a powerful HTTP networking library for Dart/Flutter
• High-level details about the monorepo structure with 50+ packages
• Language and framework information (Dart, Flutter, CMake)
• Target runtime support (Dart VM, Flutter platforms, Web browsers)

Build and Development Commands:

• Complete Melos-based workflow documentation with environment assumptions
• Validated command sequences for formatting, analysis, testing, and building
• Multi-platform testing setup (VM, Chrome/Firefox web tests, Flutter tests)
• Coverage reporting and package publishing workflows
• Clear guidance on when melos bootstrap is needed (only when dependencies change)

Project Architecture:

• Detailed directory structure with explanations
• Key configuration files and their purposes
• CI/CD pipeline documentation based on .github/workflows/tests.yml
• Dependencies and architectural patterns
• Common issues, workarounds, and performance notes

Environment Assumptions:

• Assumes Dart SDK (>=2.18.0), Flutter SDK (>=3.3.0), and Melos are pre-installed
• Code compatibility requirements for Dart >=2.18.0 and Flutter >=3.3.0
• Development environment ready for immediate use

Agent-Specific Guidance:

• Instructions to trust the documentation and only search when information is incomplete
• Efficient development workflow recommendations
• Package selection guide for different types of changes

All documented commands have been verified against the actual melos.yaml configuration to ensure accuracy. The instructions follow the 2-page limit while providing comprehensive coverage of the repository's build, test, and development processes.

Fixes #32.

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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.

[Copilot]

@kuhnroyal 👋 This repository doesn't have Copilot instructions. With Copilot instructions, I can understand the repository better, work faster and produce higher quality PRs.

I can generate a .github/copilot-instructions.md file for you automatically. Click here to open a pre-filled issue and assign it to me. I'll write the instructions, and then tag you for review.

[kuhnroyal]

@copilot Assume Dart, Flutter & melos are already installed and ready to use. melos bootstrap only needs to be run when dependencies have been changed.
Assume to always run with the latest Flutter version, but write code to always be compatible with Dart 2.18.0 and Flutter 3.3.0.

[Copilot]

@copilot Assume Dart, Flutter & melos are already installed and ready to use. melos bootstrap only needs to be run when dependencies have been changed.
Assume to always run with the latest Flutter ...

Updated the Copilot instructions to assume Dart, Flutter & Melos are already installed and clarified that melos bootstrap only needs to be run when dependencies change. Also updated compatibility requirements to specify Dart >=2.18.0 and Flutter >=3.3.0. Changes in commit aa7f182.

[github-actions]

Code Coverage Report: Only Changed Files listed

Package	Base Coverage	New Coverage	Difference
Overall Coverage	🟢 85.57%	🟢 85.57%	⚪ 0%

Minimum allowed coverage is 0%, this run produced 85.57%