Initial commit: Split Macha autonomous system into separate flake

Macha is now a standalone NixOS flake that can be imported into other
systems. This provides:

- Independent versioning
- Easier reusability
- Cleaner separation of concerns
- Better development workflow

Includes:
- Complete autonomous system code
- NixOS module with full configuration options
- Queue-based architecture with priority system
- Chunked map-reduce for large outputs
- ChromaDB knowledge base
- Tool calling system
- Multi-host SSH management
- Gotify notification integration

All capabilities from DESIGN.md are preserved.

.gitignore

@@ -0,0 +1,23 @@
+__pycache__/
+*.py[cod]
+*$py.class
+*.so
+.Python
+*.egg-info/
+dist/
+build/
+
+# IDE
+.vscode/
+.idea/
+*.swp
+*.swo
+
+# Nix
+result
+result-*
+
+# Test data
+test_*.db
+*.log
+