feat: github+gitlab integration

[ritankarsaha]

📌 Description

Please include a summary of the changes and the related issue. Provide enough context for reviewers to understand what the PR is doing.

• What problem does it solve?

Fixes #[issue-number] (if applicable)

---

Changes

The implementation includes:

Completed Features:

1. GitHub API Integration (/src/lib/github.ts)
   - Complete GitHub client using Octokit with plugins
   - Robust error handling and rate limiting
   - Maintains backward compatibility with existing hooks
2. GitLab API Integration (/src/lib/gitlab.ts)
   - Full GitLab API v4 integration with custom HTTP client
   - OAuth2 authentication support
   - Cross-platform compatibility
3. Common Type System (/src/lib/git/types.ts)
   - Unified interfaces for both platforms
   - Comprehensive type definitions for repos, issues, PRs, users, etc.
4. Shared Utilities (/src/lib/git/utils.ts)
   - Rate limiting and quota management
   - Intelligent caching with TTL and tag-based invalidation
   - HTTP client with retry logic and circuit breaker patterns
   - Environment validation and token validation
5. TypeScript Error Fixes
   - Resolved duplicate export errors
   - Added missing Node.js type definitions
   - Fixed type mismatches

Key Features Delivered:

• Production-ready: Comprehensive error handling, logging, and
  monitoring
• Secure token handling: Environment variable configuration with
  validation
• Rate limiting: Prevents API quota exhaustion
• Intelligent caching: Reduces API calls and improves performance
• Cross-platform: Unified API for both GitHub and GitLab
• Webhook support: Payload validation and processing
• Helper functions: Easy access to repo metadata, issues, and PRs

The integration is now robust, stable, and production-ready as
requested. All TypeScript errors have been resolved, and the code
follows best practices with comprehensive type safety.

Checklist

• I have tested this code
• I have added necessary documentation
• I have linked relevant issue(s)
• I followed the code style of the project
• I reviewed my own code

[Copilot]

Pull Request Overview

This PR implements comprehensive GitHub and GitLab API integrations, providing a unified interface for accessing both platforms' APIs. The implementation includes robust error handling, rate limiting, caching, and production-ready features for seamless Git platform interactions.

• Adds complete GitHub API integration using Octokit with plugins for throttling, retry, and logging
• Implements GitLab API v4 integration with custom HTTP client and OAuth2 support
• Creates unified type system and shared utilities for cross-platform compatibility

Reviewed Changes

Copilot reviewed 6 out of 7 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
src/lib/gitlab.ts	Complete GitLab API client with comprehensive error handling, rate limiting, caching, and OAuth2 support
src/lib/github.ts	GitHub API client using enhanced Octokit with plugins, maintaining backward compatibility
src/lib/git/types.ts	Unified interfaces and type definitions for both platforms
src/lib/git/utils.ts	Shared utilities including HTTP client, caching, rate limiting, and validation
package.json	Updates Node.js types to latest version
.eslintrc.json	Adds ESLint rules to handle TypeScript and regex patterns