chore: restructured the project

docs: added contributing guidelines and updated rreadme

CONTRIBUTING.md

@@ -0,0 +1,48 @@
+# Contributing to egui_knob
+
+## Getting Started
+
+1. Fork the repository
+2. Clone your fork: `git clone https://github.com/YOUR_USERNAME/egui_knob.git`
+3. Create a new branch: `git checkout -b feature/your-feature-name`
+4. Make your changes
+5. Test your changes
+6. Commit your changes
+7. Push to the branch: `git push origin feature/your-feature-name`
+8. Submit a pull request
+
+## Development
+
+### Building
+
+```bash
+cargo build
+```
+
+## Running demo app
+
+```bash
+cargo run --example example_knob
+```
+
+## Code Style
+
+- Follow Rust standard formatting (use `cargo fmt`)
+- Write clear, descriptive commit messages
+- Add documentation for public APIs
+- Keep changes focused and atomic
+
+## Pull Request Guidelines
+
+- Add examples for new features
+- Keep PRs focused on a single feature or fix
+- Reference any related issues
+
+## Reporting Issues
+
+When reporting issues, please include:
+- A clear description of the problem
+- Steps to reproduce
+- Expected vs actual behavior
+- Your environment (OS, Rust version)
+- Minimal code example if applicable