refactor code for performance and security

[juev]

This PR refactors the code to improve performance and security through several key changes including dependency injection, parallel processing with worker pools, URL normalization caching, enhanced security validation, and comprehensive testing coverage.

Key Changes:

• Dependency injection architecture: Introduces interfaces (FileSystem, CommandRunner, GitCloner, etc.) with default implementations for better testability and modularity
• Parallel processing: Implements worker pool pattern with configurable workers for concurrent repository cloning with graceful shutdown handling
• Performance optimizations: Adds URL normalization caching, regex pooling for different URL patterns, and directory existence caching with TTL and LRU eviction

[Copilot]

Pull Request Overview

This PR refactors the code to improve performance and security through several key changes including dependency injection, parallel processing with worker pools, URL normalization caching, enhanced security validation, and comprehensive testing coverage.

Key Changes:

• Dependency injection architecture: Introduces interfaces (FileSystem, CommandRunner, GitCloner, etc.) with default implementations for better testability and modularity
• Parallel processing: Implements worker pool pattern with configurable workers for concurrent repository cloning with graceful shutdown handling
• Performance optimizations: Adds URL normalization caching, regex pooling for different URL patterns, and directory existence caching with TTL and LRU eviction

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 4 comments.

File	Description
main.go	Complete refactor with dependency injection, worker pools, security enhancements, URL caching, and comprehensive error handling
main_test.go	Extensive test coverage including benchmarks, security tests, mock implementations, and worker pool functionality tests
cache_example.go	Example implementation demonstrating cache usage patterns and performance monitoring

Comments suppressed due to low confidence (4)

main.go:264

• Direct access to the global dirCache variable's mutex from test code creates tight coupling and potential race conditions. The cache manipulation should be done through the cache's public methods or the cache should be injected as a dependency.

		result.Error = fmt.Errorf("failed to determine project directory for '%s': %w", job.Repository, err)

main.go:280

• Direct access to the global urlCache.cache field without proper locking creates a race condition. This should use the cache's Set/Get methods or a proper Clear method that handles locking.

		return

main.go:291

• Another instance of unsafe direct access to the global urlCache.cache field. This creates a race condition and should use proper synchronized access methods.

	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Minute)