Fixed import error with new thumbnail system

Author: crocodilestick

CONTRIBUTORS

@@ -1,7 +1,7 @@
 CONTRIBUTORS
 
 This file is automatically generated. DO NOT EDIT MANUALLY.
-Generated on: 2025-09-14T14:20:19.788061Z
+Generated on: 2025-09-15T06:14:15.680606Z
 
 Upstream project: https://github.com/janeczku/calibre-web
 Fork project (Calibre-Web Automated, since 2024): https://github.com/crocodilestick/calibre-web-automated
@@ -298,7 +298,7 @@ Copyright (C) 2024-2025 Calibre-Web Automated contributors
 - zhiyue (1 commits)
 # Fork Contributors (crocodilestick/calibre-web-automated)
 
-- crocodilestick (662 commits)
+- crocodilestick (666 commits)
 - jmarmstrong1207 (73 commits)
 - demitrix (30 commits)
 - sirwolfgang (22 commits)

cps/helper.py

@@ -787,7 +787,6 @@ def get_book_cover_internal(book, resolution=None):
             # Try to generate missing thumbnail on-demand
             try:
                 from .tasks.thumbnail import TaskGenerateCoverThumbnails
-                from . import use_IM
 
                 # Only generate if ImageMagick is available
                 if use_IM:
@@ -987,7 +986,6 @@ def trigger_thumbnail_generation_for_book(book_id):
     """Trigger thumbnail generation for a book after cover changes."""
     try:
         from .tasks.thumbnail import TaskGenerateCoverThumbnails
-        from . import use_IM, WorkerThread
 
         if use_IM:
             # Queue thumbnail generation task