feat: add remove blank pages tool with sensitivity control

Implement new tool to detect and remove blank pages from PDFs with configurable sensitivity. Includes UI with preview functionality and comprehensive tests.

src/js/config/tools.ts

@@ -30,6 +30,7 @@ export const categories = [
             { id: 'remove-annotations', name: 'Remove Annotations', icon: 'eraser', subtitle: 'Strip comments, highlights, and links.' },
             { id: 'cropper', name: 'Crop PDF', icon: 'crop', subtitle: 'Trim the margins of every page in your PDF.' },
             { id: 'form-filler', name: 'PDF Form Filler', icon: 'square-pen', subtitle: 'Fill in forms directly in the browser.' },
+            { id: 'remove-blank-pages', name: 'Remove Blank Pages', icon: 'file-minus-2', subtitle: 'Automatically detect and delete blank pages.' },
         ]
     },
     {