fix: Abschliessen button returns to session list on last pipeline step

handleNext() did nothing on the last step (early return). Now resets
session, steps and navigates back to the session overview.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

admin-lehrer/app/(admin)/ai/ocr-pipeline/page.tsx

@@ -165,7 +165,14 @@ export default function OcrPipelinePage() {
   }
 
   const handleNext = () => {
-    if (currentStep >= steps.length - 1) return
+    if (currentStep >= steps.length - 1) {
+      // Last step completed — return to session list
+      setSteps(PIPELINE_STEPS.map((s, i) => ({ ...s, status: i === 0 ? 'active' : 'pending' })))
+      setCurrentStep(0)
+      setSessionId(null)
+      loadSessions()
+      return
+    }
 
     // Find the next non-skipped step
     const skipSteps = docTypeResult?.skip_steps || []