✨ Set up comprehensive Copilot instructions

[Copilot]

Configured comprehensive Copilot instructions for the Remarklet repository following GitHub's best practices for Copilot coding agents.

Overview

Enhanced the existing .github/copilot-instructions.md file from basic coding guidelines to a comprehensive development guide that provides AI assistants and contributors with detailed context about the project architecture, workflows, and conventions.

Key Improvements

Project Context

• Added detailed project overview explaining Remarklet's purpose as a visual web page editing library
• Documented key features including drag-and-drop, text editing, CSS manipulation, and touch support
• Provided clear architecture description of the ES6 module library structure

Development Workflow

• Complete setup instructions with Node.js version requirements
• Comprehensive npm scripts documentation for build, test, and lint processes
• Testing strategy covering both Playwright E2E tests and Node.js unit tests

Enhanced Coding Standards

• JavaScript/TypeScript specific conventions with concrete examples
• API design patterns for module structure and DOM interactions
• Error handling and debugging guidelines with code examples
• Performance considerations for DOM manipulation and memory management

Documentation & Contribution Guidelines

• JSDoc standards with comprehensive examples
• Browser compatibility requirements and testing approach
• Troubleshooting section for common development issues
• Clear contribution workflow references

Technical Details

The enhanced instructions now provide guidance for:

• Module organization in the src/ directory with detailed component descriptions
• Build process using Rollup bundling and TypeScript definition generation
• Testing patterns for both E2E browser testing and unit testing
• CSS management patterns and DOM interaction best practices

This follows the referenced best practices guide to help Copilot provide more accurate and context-aware assistance when working on the Remarklet codebase.

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 #222

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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.