Sticky Sidebar Navigation Across All Pages

## What's New
The sidebar navigation on all logged-in pages, including billing, dashboard, settings, and more, has been updated to feature a sticky position. This change allows the sidebar to remain visible and accessible as users scroll down the page, improving navigation and making it easier to switch between sections without losing context.

This enhancement is particularly beneficial for users who frequently access different areas of the application, as it streamlines the overall browsing experience. Enjoy a more efficient and user-friendly interface with this update!