Refactor TodoItem and CreateModal to simplify state management and remove unused code

src/vite-env.d.ts

@@ -3,7 +3,7 @@
 declare module '*.vue' {
   import type { DefineComponent } from 'vue'
 
-  const component: DefineComponent<{}, {}, any>
+  const component: DefineComponent<object, object, any>
   export default component
 }