Add comprehensive GitHub Copilot instructions for development workflow

[Copilot]

This PR adds a comprehensive .github/copilot-instructions.md file that provides GitHub Copilot with detailed instructions for working effectively in this React TypeScript component library codebase.

Key Features

Complete Development Workflow Coverage:

• Bootstrap instructions with exact commands and timing expectations
• Build, test, lint, and format workflows with validated commands
• Storybook development and component validation procedures
• Manual testing scenarios for ensuring changes work correctly

Validated Command Documentation:
All commands have been thoroughly tested and include:

• Exact timing measurements (npm ci: 6-48s, build: ~10s, tests: ~3s)
• Explicit timeout recommendations with "NEVER CANCEL" warnings
• Known warnings and issues documented as expected behavior
• Complete validation chains for pre-commit checks

Component Development Guidance:

• Instructions for adding new components with Storybook stories
• Validation procedures using the component demo at localhost:6006
• Project structure explanation with atomic design organization
• Key files and areas that frequently need attention

Technical Specifications:

• Build system details (Vite, TypeScript, ES modules)
• Testing framework setup (Vitest with 18 existing tests)
• Linting/formatting with Biome configuration
• Library packaging and export structure

The instructions follow an imperative tone ("Run this command", "Do not do this") and prioritize actionable information that will help Copilot avoid common mistakes and work efficiently with the existing codebase.

All commands and workflows have been validated through complete fresh installation and testing cycles to ensure accuracy.

Fixes #115.

Warning

Firewall rules blocked me from connecting to one or more addresses

I tried to connect to the following addresses, but was blocked by firewall rules:

• storybook.js.org
  • Triggering command: node /home/REDACTED/work/glowing-telegram-video-editor/glowing-telegram-video-editor/node_modules/.bin/storybook dev -p 6006 (dns block)
  • Triggering command: node /home/REDACTED/work/glowing-telegram-video-editor/glowing-telegram-video-editor/node_modules/.bin/storybook build (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

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

[Copilot]

Pull Request Overview

This PR adds comprehensive GitHub Copilot development instructions to establish effective workflows for a React TypeScript component library. The instructions provide detailed guidance for build processes, testing, and development practices to help Copilot work efficiently with the codebase.

• Complete development workflow documentation with validated commands and timing expectations
• Comprehensive validation procedures for manual testing and pre-commit checks
• Project structure guidance and component development best practices