feat: web worker for image to pdf processing

[shivam-bit]

Problem Statement

The application freezes when executing the downloadImagesAsPdf function, which involves heavy computation for image processing and PDF generation. This occurs due to the execution of resource-intensive tasks on the main thread, leading to a degradation in UI responsiveness.

Expected Behavior

The application should maintain a responsive user interface even during resource-intensive tasks, such as image processing and PDF generation.

Proposed Solution

To address the freezing issue, we propose moving the heavy computation to a Web Worker, which runs in the background and doesn't block the main thread. The Web Worker will handle image processing and PDF generation asynchronously.