feat(ui): workspace tabs use the shared counter

To-Dos and Hashtags show a CountBadge on the label like all other tabs;
Notizen has no counter any more.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

frontend/src/features/workspace/WorkspaceView.tsx

@@ -1223,7 +1223,6 @@ export const WorkspaceView: React.FC<WorkspaceViewProps> = ({
           >
             <FileText className="w-3.5 h-3.5 text-accent" />
             <span>Notizen</span>
-            {docs.length > 0 && <span className="ml-1 badge-neutral text-[10px]">{docs.length}</span>}
           </button>
 
           <button
@@ -1239,8 +1238,10 @@ export const WorkspaceView: React.FC<WorkspaceViewProps> = ({
             }`}
           >
             <Check className="w-3.5 h-3.5 text-status-ok" />
-            <span>To-Dos</span>
+            <span className={`relative inline-flex items-center ${totalOpenTodos > 0 ? 'pr-2' : ''}`}>
-            {totalOpenTodos > 0 && <span className="ml-1 badge-neutral text-[10px]">{totalOpenTodos}</span>}
+              To-Dos
+              <CountBadge count={totalOpenTodos} position="corner" className="-top-1.5 -right-1" />
+            </span>
           </button>
 
           <button
@@ -1256,8 +1257,10 @@ export const WorkspaceView: React.FC<WorkspaceViewProps> = ({
             }`}
           >
             <Hash className="w-3.5 h-3.5 text-accent" />
-            <span>Hashtags</span>
+            <span className={`relative inline-flex items-center ${tagsSummary.length > 0 ? 'pr-2' : ''}`}>
-            {tagsSummary.length > 0 && <span className="ml-1 badge-neutral text-[10px]">{tagsSummary.length}</span>}
+              Hashtags
+              <CountBadge count={tagsSummary.length} position="corner" className="-top-1.5 -right-1" />
+            </span>
           </button>
         </div>