Summary

This pull request implements support for yarn as a resolver, addressing issue #19. The yarn resolver allows use-m to install and resolve packages using yarn instead of npm or other resolvers.

🔧 Implementation Details

New yarn resolver features:

• Package installation: Uses yarn global add for package installation
• Global directory detection: Uses yarn global dir to find the correct installation path
• Version management: Checks installed package versions to avoid unnecessary reinstalls
• Module resolution: Follows yarn's simpler global directory structure (packages installed directly by name)
• Full compatibility: Supports all module specifier formats:
  • Basic packages: lodash@4.17.21
  • Scoped packages: @octokit/core@6.1.5
  • Subpaths: yargs@17.7.2/helpers
  • Latest versions: package@latest

Code changes:

• Added yarn resolver to both use.mjs and use.cjs
• Added comprehensive test coverage in tests/resolvers.test.mjs
• Created demo script examples/yarn-resolver-demo.mjs to showcase functionality
• Bumped version to 8.14.0

🧪 Test Coverage

• ✅ Basic package resolution (lodash@4.17.21)
• ✅ Scoped package resolution (@octokit/core@6.1.5)
• ✅ Subpath resolution (yargs@17.7.2/helpers)
• ✅ Latest version handling (yargs@latest/helpers)
• ✅ All tests passing with automated CI

📋 Usage Example

import { makeUse } from 'use-m';

// Create a use function with yarn resolver
const use = await makeUse({
  specifierResolver: 'yarn'
});

// Use packages installed via yarn
const lodash = await use('lodash@4.17.21');
const yargHelpers = await use('yargs@17.7.2/helpers');

🎯 Key Differences from npm/bun resolvers

• Simpler directory structure: Yarn installs packages directly by their original names rather than using versioned aliases
• Version checking: Reads package.json to verify installed version matches requested version
• Global directory handling: Uses yarn global dir command to detect the correct global installation path

✅ Verification

• All existing tests continue to pass
• New yarn resolver tests pass successfully
• Demo script demonstrates working functionality
• Integration with existing codebase is seamless

Fixes #19

This implementation follows the established patterns from existing resolvers while accommodating yarn's unique global package management approach.