refactor: improve error handling and code formatting

- Enhanced error messages in Rust backend to include file paths
- Improved provider switching error handling with detailed messages
- Added MCP button placeholder in UI (functionality TODO)
- Applied code formatting across frontend components
- Extended error notification duration to 6s for better readability

src/main.tsx

@@ -25,5 +25,5 @@ ReactDOM.createRoot(document.getElementById("root")!).render(
     <UpdateProvider>
       <App />
     </UpdateProvider>
-  </React.StrictMode>
+  </React.StrictMode>,
 );