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/structure.py

@@ -15,9 +15,9 @@ import numpy as np
 from fastapi import APIRouter, HTTPException
 from pydantic import BaseModel
 
-from cv_box_detect import detect_boxes
-from cv_color_detect import _COLOR_RANGES, _COLOR_HEX
-from cv_graphic_detect import detect_graphic_elements
+from ocr.detect.box_detect import detect_boxes
+from ocr.detect.color_detect import _COLOR_RANGES, _COLOR_HEX
+from ocr.detect.graphic_detect import detect_graphic_elements
 from .session_store import (
     get_session_db,
     update_session_db,
@@ -100,7 +100,7 @@ async def detect_structure(session_id: str):
     )
 
     # --- Zone splitting ---
-    from cv_box_detect import split_page_into_zones as _split_zones
+    from ocr.detect.box_detect import split_page_into_zones as _split_zones
     zones = _split_zones(content_x, content_y, content_w_px, content_h_px, boxes)
 
     # --- Color region sampling ---
@@ -123,7 +123,7 @@ async def detect_structure(session_id: str):
             med_s = float(np.median(roi_hsv[:, :, 1]))
             med_v = float(np.median(roi_hsv[:, :, 2]))
             if med_s > 15:
-                from cv_color_detect import _hue_to_color_name
+                from ocr.detect.color_detect import _hue_to_color_name
                 bg_name = _hue_to_color_name(med_h)
                 bg_hex = _COLOR_HEX.get(bg_name, "#6b7280")
             else: