refactor: introduce dedicated identifier types for improved clarity and type safety

frontend/src/app/useWorkspaceSelection.ts

@@ -10,8 +10,8 @@ interface SelectionEntry {
 }
 
 interface WorkspaceSelectionOptions {
-  onDocumentActivate?: (id: string | number) => void;
-  onInspectFolder?: (id: string | number) => void;
+  onDocumentActivate?: (id: string) => void;
+  onInspectFolder?: (id: string) => void;
 }
 
 const identity = <T,>(value: T) => value;
@@ -71,7 +71,7 @@ export const useWorkspaceSelection = ({
   );
 
   const inspectDocument = useCallback(
-    (documentId?: string | number) => {
+    (documentId?: string) => {
       if (!documentId) return;
       onDocumentActivate(documentId);
     },
@@ -79,7 +79,7 @@ export const useWorkspaceSelection = ({
   );
 
   const inspectFolder = useCallback(
-    (folderId?: string | number) => {
+    (folderId?: string) => {
       if (!folderId) return;
       onInspectFolder(folderId);
     },