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/ocr/pipeline/words_detect.py

@@ -17,7 +17,7 @@ import numpy as np
 from fastapi import APIRouter, HTTPException, Request
 from fastapi.responses import StreamingResponse
 
-from cv_vocab_pipeline import (
+from ocr.cv_pipeline import (
     PageRegion,
     RowGeometry,
     _cells_to_vocab_entries,
@@ -27,7 +27,7 @@ from cv_vocab_pipeline import (
     create_ocr_image,
     detect_column_geometry,
 )
-from cv_words_first import build_grid_from_words
+from ocr.words_first import build_grid_from_words
 from .session_store import (
     get_session_db,
     update_session_db,
@@ -223,7 +223,7 @@ async def _words_first_path(
     img_h, img_w = dewarped_bgr.shape[:2]
 
     if engine == "paddle":
-        from cv_ocr_engines import ocr_region_paddle
+        from ocr.engines.engines import ocr_region_paddle
         wf_word_dicts = await ocr_region_paddle(dewarped_bgr, region=None)
         cached["_paddle_word_dicts"] = wf_word_dicts
     else: