Fix: Update all old-style imports inside packages to new paths

65 files in klausur-service packages + 3 in backend-lehrer packages
had stale imports referencing deleted shim modules.

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

klausur-service/backend/vocab/worksheet/analysis_api.py

@@ -27,7 +27,7 @@ from .generation import convert_pdf_page_to_image
 
 # Try to import Tesseract extractor
 try:
-    from tesseract_vocab_extractor import (
+    from ocr.engines.tesseract_extractor import (
         extract_bounding_boxes, TESSERACT_AVAILABLE,
     )
 except ImportError:
@@ -264,7 +264,7 @@ async def extract_with_boxes(session_id: str, page_number: int):
     # Deskew image before OCR
     deskew_angle = 0.0
     try:
-        from cv_vocab_pipeline import deskew_image_by_word_alignment, CV2_AVAILABLE
+        from ocr.cv_pipeline import deskew_image_by_word_alignment, CV2_AVAILABLE
         if CV2_AVAILABLE:
             image_data, deskew_angle = deskew_image_by_word_alignment(image_data)
             logger.info(f"Deskew: {deskew_angle:.2f}° for page {page_number}")