feat: implement universal issue tracking facade

Add comprehensive issue tracking facade system that provides a unified CLI interface to any issue tracking backend. The facade automatically detects the repository's issue tracker and provides consistent commands across all platforms.

Key features:
- Repository-aware automatic backend detection (GitHub, GitLab, Gitea, local SQLite)
- Unified CLI interface with same commands across all backends
- Plugin architecture for extensible backend support
- Local SQLite backend for offline development
- Gitea backend with full API integration
- Bidirectional synchronization between backends
- Performance-optimized domain models with caching
- Clean architecture with separation of concerns

The facade acts as a "universal remote control" for issue tracking systems, eliminating the need to learn different CLIs for each platform while providing seamless offline capability and cross-platform consistency.

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

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

issue-facade/__init__.py

@@ -0,0 +1,24 @@
+"""
+Universal Issue Tracking System
+
+A backend-agnostic issue tracking system that supports multiple backends
+through a plugin architecture. Designed to be extracted into a standalone
+repository for use across multiple projects.
+
+Features:
+- Unified issue model across all backends
+- Plugin-based backend architecture
+- Local SQLite backend for offline work
+- Bidirectional synchronization
+- CLI-first interface
+- Support for GitHub-style and other issue tracking systems
+
+Supported Backends:
+- Local SQLite (for offline/standalone use)
+- Gitea (GitHub-compatible API)
+- Future: GitHub, GitLab, JIRA, Redmine, etc.
+"""
+
+__version__ = "0.1.0"
+__author__ = "MarkiTect Project"
+__description__ = "Universal Issue Tracking System with Plugin Architecture"