feat: add Einführung button to annotation top bar that navigates back to the intro screen

src/components/AnnotationViews/AnnotationPageView.tsx

@@ -24,12 +24,14 @@ interface AnnotationPageViewProps {
   entries: DatasetEntryForAnnotation[];
   experimentId: number;
   viewType: string;
+  onShowIntro?: () => void;
 }
 
-export default function AnnotationPageView({ 
-  entries, 
+export default function AnnotationPageView({
+  entries,
   experimentId,
   viewType,
+  onShowIntro,
 }: AnnotationPageViewProps) {
 
   const [isPending, startTransition] = useTransition();
@@ -287,6 +289,15 @@ export default function AnnotationPageView({
                   </svg>
                 </button>
 
+                {onShowIntro && (
+                  <button
+                    onClick={onShowIntro}
+                    className="text-sm px-3 py-1.5 bg-gray-100 hover:bg-gray-200 text-gray-700 rounded-md transition-colors"
+                  >
+                    ← Einführung
+                  </button>
+                )}
+
                 {Object.keys(dialectScores).length > 0 && (
                   <button
                     onClick={() => setIsCalibrationModalOpen(true)}

src/components/AnnotationViews/AnnotationPhase.tsx

@@ -29,5 +29,5 @@ export default function AnnotationPhase({
     );
   }
 
-  return <AnnotationPageView entries={entries} experimentId={experimentId} viewType={viewType} />;
+  return <AnnotationPageView entries={entries} experimentId={experimentId} viewType={viewType} onShowIntro={() => setShowInfoPage(true)} />;
 }