feat(mcp): implement Git Operations MCP server with Gitea provider

Implements the Git Operations MCP server (Issue #58) providing:

Core features:
- GitPython wrapper for local repository operations (clone, commit, push, pull, diff, log)
- Branch management (create, delete, list, checkout)
- Workspace isolation per project with file-based locking
- Gitea provider for remote PR operations

MCP Tools (17 registered):
- clone_repository, git_status, create_branch, list_branches
- checkout, commit, push, pull, diff, log
- create_pull_request, get_pull_request, list_pull_requests
- merge_pull_request, get_workspace, lock_workspace, unlock_workspace

Technical details:
- FastMCP + FastAPI with JSON-RPC 2.0 protocol
- pydantic-settings for configuration (env prefix: GIT_OPS_)
- Comprehensive error hierarchy with structured codes
- 131 tests passing with 67% coverage
- Async operations via ThreadPoolExecutor

Closes: #105, #106, #107, #108, #109

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

mcp-servers/git-ops/providers/__init__.py

@@ -0,0 +1,10 @@
+"""
+Git provider implementations.
+
+Provides adapters for different git hosting platforms (Gitea, GitHub, GitLab).
+"""
+
+from .base import BaseProvider
+from .gitea import GiteaProvider
+
+__all__ = ["BaseProvider", "GiteaProvider"]