fix: auto-trigger orientation for page-split sessions without result

Page-split sessions (start_step=1) have no orientation_result stored.
StepOrientation now auto-runs orientation detection when loading an
existing session that lacks a result.

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

admin-lehrer/components/ocr-pipeline/StepOrientation.tsx

@@ -30,7 +30,7 @@ export function StepOrientation({ sessionId: existingSessionId, onNext, onSessio
   const [dragOver, setDragOver] = useState(false)
   const [sessionName, setSessionName] = useState('')
 
-  // Reload session data when navigating back
+  // Reload session data when navigating back — auto-trigger orientation if missing
   useEffect(() => {
     if (!existingSessionId || session) return
 
@@ -51,6 +51,28 @@ export function StepOrientation({ sessionId: existingSessionId, onNext, onSessio
 
         if (data.orientation_result) {
           setOrientationResult(data.orientation_result)
+        } else {
+          // Session exists but orientation not yet run (e.g. page-split session)
+          // Auto-trigger orientation detection
+          setDetecting(true)
+          try {
+            const orientRes = await fetch(
+              `${KLAUSUR_API}/api/v1/ocr-pipeline/sessions/${existingSessionId}/orientation`,
+              { method: 'POST' },
+            )
+            if (orientRes.ok) {
+              const orientData = await orientRes.json()
+              setOrientationResult({
+                orientation_degrees: orientData.orientation_degrees,
+                corrected: orientData.corrected,
+                duration_seconds: orientData.duration_seconds,
+              })
+            }
+          } catch (e) {
+            console.error('Auto-orientation failed:', e)
+          } finally {
+            setDetecting(false)
+          }
         }
       } catch (e) {
         console.error('Failed to reload session:', e)