Switch from ESLint to Biome for linting and styling

[Copilot]

This PR migrates the project from ESLint to Biome as the primary tool for linting and code style enforcement, providing a faster and more comprehensive development experience.

Changes Made

🔄 Migration Process

• Automated migration: Used Biome's built-in ESLint migration tool to preserve existing code quality standards
• Rule coverage: Successfully migrated 78% (69/88) of ESLint rules to Biome equivalents
• Configuration: Created biome.json with TypeScript support and project-specific formatting preferences

📦 Dependencies

• Added: @biomejs/biome as dev dependency
• Removed: All ESLint-related dependencies:
  • @eslint/js
  • @types/eslint
  • eslint
  • globals
  • typescript-eslint

📝 Scripts & Configuration

• Updated package.json scripts:
  • lint: Now runs biome check .
  • lint:fix: Now runs biome check --write .
• Removed: eslint.config.js
• Added: biome.json with comprehensive TypeScript linting and formatting rules

📖 Documentation

• Updated README.md to reference Biome instead of ESLint
• Updated project structure documentation
• Updated technology stack description

Benefits

• Performance: Biome is significantly faster than ESLint for large codebases
• Unified tooling: Combines linting, formatting, and import sorting in one tool
• Better TypeScript support: Native TypeScript support without additional plugins
• Consistent formatting: Enforces consistent code style across the project

Testing

All existing functionality remains intact:

• ✅ Build process (pnpm build)
• ✅ Test suite (pnpm test:run)
• ✅ Linting (pnpm lint)
• ✅ Auto-fixing (pnpm lint:fix)

Fixes #5.

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