Unify Repository Endpoints and Add Multi-Provider Support

[zmotso]

Summary

This refactor unifies repository endpoints for all supported Git providers (GitHub, GitLab, Bitbucket) and introduces a dynamic, map-based multi-provider service for repository operations. The API and backend logic are now provider-agnostic and easier to extend.

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Details

API Changes

• Replaced all provider-specific endpoints with two generic endpoints:
  • GET /api/v1/repositories — List repositories (requires gitServer and owner, optional repoName)
  • GET /api/v1/repository — Get repository details (requires gitServer, owner, and repoName)
• All parameters are now query parameters.
• Response schemas are now provider-agnostic.

Handler Refactor

• Removed provider-specific handlers (GitHub, GitLab, Bitbucket).
• Added a single RepositoryHandler to handle all repository-related requests for all providers.
• Updated server wiring to use the new handler and endpoints.

Multi-Provider Service

• Added a MultiProviderService that uses a map to dispatch repository operations to the correct provider implementation (GitHubService, GitlabService, BitbucketService) based on the GitProvider field in GitProviderSettings.
• Follows the Strategy pattern for extensibility and maintainability.

Supporting Changes

• Deprecated and replaced all provider-specific handler files.
• Updated handler registration and server construction to use the new multi-provider service.

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Motivation

• Simplifies the API for clients.
• Reduces code duplication and maintenance overhead.
• Makes it easy to add support for new providers in the future.
• Follows Go best practices and the Strategy design pattern.