feat: Orientierung + Zuschneiden als Schritte 1-2 in OCR-Pipeline

Zwei neue Wizard-Schritte vor Begradigung:
- Step 1: Orientierungserkennung (0/90/180/270° via Tesseract OSD)
- Step 2: Seitenrand-Erkennung und Zuschnitt (Scannerraender entfernen)

Backend:
- orientation_crop_api.py: POST /orientation, POST /crop, POST /crop/skip
- page_crop.py: detect_and_crop_page() mit Format-Erkennung (A4/A5/Letter)
- Session-Store: orientation_result, crop_result Felder
- Pipeline nutzt zugeschnittenes Bild fuer Deskew/Dewarp

Frontend:
- StepOrientation.tsx: Upload + Auto-Orientierung + Vorher/Nachher
- StepCrop.tsx: Auto-Crop + Format-Badge + Ueberspringen-Option
- Pipeline-Stepper: 10 Schritte (war 8)

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

klausur-service/backend/ocr_pipeline_session_store.py

@@ -68,7 +68,11 @@ async def init_ocr_pipeline_tables():
             ADD COLUMN IF NOT EXISTS doc_type VARCHAR(50),
             ADD COLUMN IF NOT EXISTS doc_type_result JSONB,
             ADD COLUMN IF NOT EXISTS document_category VARCHAR(50),
-            ADD COLUMN IF NOT EXISTS pipeline_log JSONB
+            ADD COLUMN IF NOT EXISTS pipeline_log JSONB,
+            ADD COLUMN IF NOT EXISTS oriented_png BYTEA,
+            ADD COLUMN IF NOT EXISTS cropped_png BYTEA,
+            ADD COLUMN IF NOT EXISTS orientation_result JSONB,
+            ADD COLUMN IF NOT EXISTS crop_result JSONB
         """)
 
 
@@ -90,6 +94,7 @@ async def create_session_db(
                 id, name, filename, original_png, status, current_step
             ) VALUES ($1, $2, $3, $4, 'active', 1)
             RETURNING id, name, filename, status, current_step,
+                      orientation_result, crop_result,
                       deskew_result, dewarp_result, column_result, row_result,
                       word_result, ground_truth, auto_shear_degrees,
                       doc_type, doc_type_result,
@@ -106,6 +111,7 @@ async def get_session_db(session_id: str) -> Optional[Dict[str, Any]]:
     async with pool.acquire() as conn:
         row = await conn.fetchrow("""
             SELECT id, name, filename, status, current_step,
+                   orientation_result, crop_result,
                    deskew_result, dewarp_result, column_result, row_result,
                    word_result, ground_truth, auto_shear_degrees,
                    doc_type, doc_type_result,
@@ -123,6 +129,8 @@ async def get_session_image(session_id: str, image_type: str) -> Optional[bytes]
     """Load a single image (BYTEA) from the session."""
     column_map = {
         "original": "original_png",
+        "oriented": "oriented_png",
+        "cropped": "cropped_png",
         "deskewed": "deskewed_png",
         "binarized": "binarized_png",
         "dewarped": "dewarped_png",
@@ -150,15 +158,17 @@ async def update_session_db(session_id: str, **kwargs) -> Optional[Dict[str, Any
 
     allowed_fields = {
         'name', 'filename', 'status', 'current_step',
-        'original_png', 'deskewed_png', 'binarized_png', 'dewarped_png',
+        'original_png', 'oriented_png', 'cropped_png',
+        'deskewed_png', 'binarized_png', 'dewarped_png',
         'clean_png', 'handwriting_removal_meta',
+        'orientation_result', 'crop_result',
         'deskew_result', 'dewarp_result', 'column_result', 'row_result',
         'word_result', 'ground_truth', 'auto_shear_degrees',
         'doc_type', 'doc_type_result',
         'document_category', 'pipeline_log',
     }
 
-    jsonb_fields = {'deskew_result', 'dewarp_result', 'column_result', 'row_result', 'word_result', 'ground_truth', 'handwriting_removal_meta', 'doc_type_result', 'pipeline_log'}
+    jsonb_fields = {'orientation_result', 'crop_result', 'deskew_result', 'dewarp_result', 'column_result', 'row_result', 'word_result', 'ground_truth', 'handwriting_removal_meta', 'doc_type_result', 'pipeline_log'}
 
     for key, value in kwargs.items():
         if key in allowed_fields:
@@ -182,6 +192,7 @@ async def update_session_db(session_id: str, **kwargs) -> Optional[Dict[str, Any
             SET {', '.join(fields)}
             WHERE id = ${param_idx}
             RETURNING id, name, filename, status, current_step,
+                      orientation_result, crop_result,
                       deskew_result, dewarp_result, column_result, row_result,
                       word_result, ground_truth, auto_shear_degrees,
                       doc_type, doc_type_result,
@@ -254,7 +265,7 @@ def _row_to_dict(row: asyncpg.Record) -> Dict[str, Any]:
             result[key] = result[key].isoformat()
 
     # JSONB → parsed (asyncpg returns str for JSONB)
-    for key in ['deskew_result', 'dewarp_result', 'column_result', 'row_result', 'word_result', 'ground_truth', 'doc_type_result', 'pipeline_log']:
+    for key in ['orientation_result', 'crop_result', 'deskew_result', 'dewarp_result', 'column_result', 'row_result', 'word_result', 'ground_truth', 'doc_type_result', 'pipeline_log']:
         if key in result and result[key] is not None:
             if isinstance(result[key], str):
                 result[key] = json.loads(result[key])