Added modals for popups, and fixed root-level bug.

Frontend/src/App.jsx

@@ -7,6 +7,7 @@ import DirectoryPane from "./Components/DirectoryPane.jsx";
 import TagPanel from "./Components/TagPanel.jsx";
 import SettingsPanel from "./Components/SettingsPanel.jsx";
 import LoginScreen from "./Components/LoginScreen.jsx";
+import ErrorToast from "./Components/ErrorToast.jsx";
 import {
   EnsureDirectoryNote,
   FetchAuthStatus,
@@ -69,6 +70,7 @@ export default function App() {
   const [SidebarKey, SetSidebarKey] = useState(0);
   const [Settings, SetSettings] = useState(null);
   const [IsSettingsOpen, SetIsSettingsOpen] = useState(false);
+  const [ErrorMessage, SetErrorMessage] = useState(null);
 
   useEffect(() => {
     FetchAuthStatus().then((Status) => {
@@ -237,7 +239,7 @@ export default function App() {
       const Created = await EnsureDirectoryNote(ActiveRoot, DirectoryPath);
       HandleSelectDirectoryNote(DirectoryPath, Created.Name, Created.FileType);
     } catch (Error) {
-      window.alert(Error.message);
+      SetErrorMessage(Error.message);
     }
   }
 
@@ -391,6 +393,7 @@ export default function App() {
           OnProfileUpdated={HandleProfileUpdated}
         />
       )}
+      <ErrorToast Message={ErrorMessage} OnDismiss={() => SetErrorMessage(null)} />
     </div>
   );
 }