refactor: remove obsolete issue management system in favor of issue-facade

Complete cleanup of the legacy TDD AI and issue management system, establishing clear separation of concerns as requested. All issue handling is now provided by the standalone issue-facade system.

Removed components:
- TDD AI framework (tddai/ directory and tddai_cli.py)
- Legacy issue management CLI commands and services
- Issue-related Makefile targets and helper commands
- Obsolete tests and infrastructure dependencies
- Finance modules that depended on the old issue system

Updated:
- Makefile: Removed issue-*, tdd-*, and test-from-issue commands
- CLI framework: Simplified to core functionality only
- Documentation: Added deprecation notice for old config system

The issue-facade now serves as the universal CLI for issue tracking,
providing backend-agnostic interface to GitHub, GitLab, Gitea, and
local SQLite storage as documented in issue-facade/README.md.

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

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

CONFIG.md

@@ -1,5 +1,9 @@
 # TDDAi Configuration Management
 
+> **⚠️ DEPRECATED**: The tddai framework has been replaced by the [issue-facade](issue-facade/) system. This documentation is kept for historical reference only.
+>
+> **For current issue management**: See [issue-facade/README.md](issue-facade/README.md)
+
 The tddai framework uses a flexible, hierarchical configuration system designed for project-agnostic deployment while supporting per-project customization.
 
 ## Configuration Hierarchy