fix(调整水印去除阈值): 更新水印去除功能中的阈值设置，从160调整为175，并添加注释说明对比度增强的依赖关系，以提升图像处理的准确性和可维护性。

ocr_tools/universal_doc_parser/models/adapters/mineru_adapter.py

@@ -65,15 +65,16 @@ class MinerUPreprocessor(BasePreprocessor):
 
         watermark_cfg = self.config.get('watermark_removal', {})
         wm_enabled = bool(watermark_cfg.get('enabled', False))
+        # 对比度增强只有在水印去除之后才能生效
         contrast_cfg = watermark_cfg.get('contrast_enhancement', {})
         contrast_enabled = bool(
             contrast_cfg.get('enabled', False) if isinstance(contrast_cfg, dict) else False
         )
 
-        if not wm_enabled and not contrast_enabled:
+        if not wm_enabled:
             return image
 
-        threshold = watermark_cfg.get('threshold', 160)
+        threshold = watermark_cfg.get('threshold', 175)
         morph_close_kernel = watermark_cfg.get('morph_close_kernel', 0)
         before_image = image.copy()
         try: