feat: Fix D-Bus type compatibility and establish successful daemon communication

- Fix D-Bus type errors by flattening status dictionary
- Remove nested 'config' dictionary that caused TypeError
- Convert all values to D-Bus-compatible types (string, int, bool, double)
- Confirm production security policy working (root-only access)
- Successfully test GetStatus method with valid response
- Update D-Bus policy to allow root access to specific interfaces
- Update CHANGELOG.md with D-Bus communication milestone
- Update TODO.md to reflect completed daemon integration

The apt-ostree daemon now has working D-Bus communication with proper
type handling and production-ready security policies. Ready for full
integration with apt-layer.sh client.

TODO.md

@@ -35,8 +35,13 @@
 
 ### VM Testing & Daemon Integration
 - ✅ VM environment setup and apt-layer/apt-ostree integration testing
-- 🔄 Diagnosing daemon startup issue: Python entry point not launching daemon as expected
-- 🔄 Next: Verify Python package install, test running daemon directly, fix entry point/install process
+- ✅ Daemon startup and D-Bus registration working correctly
+- ✅ D-Bus communication established with proper method signatures
+- ✅ D-Bus type compatibility resolved (flattened status dictionary)
+- ✅ Production security policy confirmed (root-only access)
+- ✅ GetStatus method tested and returning valid responses
+- 🎯 Next: Implement additional D-Bus methods (InstallPackages, RemovePackages, etc.)
+- 🎯 Next: Integrate with apt-layer.sh client for full daemon orchestration
 
 ## Next Phase 🎯