Add initial project structure with Rust Nix flake template

- Create .envrc for Direnv configuration
- Add .pre-commit-config.yaml for pre-commit hooks
- Include CONTRIBUTING.md for contribution guidelines
- Initialize Cargo.toml for Rust package configuration
- Update LICENSE to link to full license text
- Create Makefile for build, run, test, and clean commands
- Revise README.md for project description and usage instructions
- Implement default Nix flake configuration in flake.nix
- Add Flatpak manifest for packaging
- Set up project metadata in project.toml
- Create shell.nix for legacy shell support
- Add skeletal Rust application in src/main.rs
- Include sample test in tests/sample_test.rs

tests/sample_test.rs

@@ -0,0 +1,4 @@
+#[test]
+fn test_sample() {
+    assert_eq!(1, 1);
+}