refactor: add delete option to sidebar

Todos/View/ContentView.swift

@@ -20,6 +20,10 @@ struct ContentView: View {
             CategoryPanelView(item: item)
           } label: {
             CategorySidebarView(name: Bindable(item).name)
+          } .contextMenu {
+            Button(action: { deleteItem(item: item) }) {
+              Label("Delete", systemImage: "trash")
+            }
           }
         }
         .onDelete(perform: deleteItems)
@@ -47,6 +51,12 @@ struct ContentView: View {
       modelContext.insert(newItem)
     }
   }
+  
+  private func deleteItem(item: Category) {
+    withAnimation {
+      modelContext.delete(item)
+    }
+  }
 
   private func deleteItems(offsets: IndexSet) {
     withAnimation {