Show detected page number in session header

Extracts page_number from grid_editor_result when opening a session
and displays it as "S. 233" badge in the SessionHeader, next to the
category and GT badges.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

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

@@ -27,6 +27,7 @@ function OcrKombiContent() {
     loadingSessions,
     activeCategory,
     isGroundTruth,
+    pageNumber,
     steps,
     gridSaveRef,
     groupedSessions,
@@ -142,6 +143,7 @@ function OcrKombiContent() {
           sessionName={sessionName}
           activeCategory={activeCategory}
           isGroundTruth={isGroundTruth}
+          pageNumber={pageNumber}
           onUpdateCategory={(cat) => updateCategory(sessionId, cat)}
         />
       )}

admin-lehrer/app/(admin)/ai/ocr-kombi/useKombiPipeline.ts

@@ -33,6 +33,7 @@ export function useKombiPipeline() {
   const [loadingSessions, setLoadingSessions] = useState(true)
   const [activeCategory, setActiveCategory] = useState<DocumentCategory | undefined>(undefined)
   const [isGroundTruth, setIsGroundTruth] = useState(false)
+  const [pageNumber, setPageNumber] = useState<number | null>(null)
   const [steps, setSteps] = useState<PipelineStep[]>(initSteps())
 
   const searchParams = useSearchParams()
@@ -123,6 +124,7 @@ export function useKombiPipeline() {
       setSessionName(data.name || data.filename || '')
       setActiveCategory(data.document_category || undefined)
       setIsGroundTruth(!!data.ground_truth?.build_grid_reference)
+      setPageNumber(data.grid_editor_result?.page_number?.number ?? null)
 
       // Determine UI step from DB state
       const dbStep = data.current_step || 1
@@ -275,6 +277,7 @@ export function useKombiPipeline() {
     loadingSessions,
     activeCategory,
     isGroundTruth,
+    pageNumber,
     steps,
     gridSaveRef,
     // Computed