This is WIP PR on new Tabler flat layout

Overview

This PR introduces a new layout implementation (currently at preview/pages/_layouts/flat.html). Since the Tabler core structure has undergone significant changes since my last contribution, I’m seeking guidance on properly organizing the layout files, assets (CSS/SCSS, JS), and partials.

What's Changed

• Layout File: Introduced flat.html in preview/pages/_layouts/ as a new layout.
• Entry Point: Noticed that base.html now serves as the main entry point using a yield content mechanism.

Questions & Guidance Needed

1. File Organization:
   • How should the new layout be split into proper files (CSS/SCSS, JS, partials)?
   • Are there recommended directories or naming conventions for these assets in the current structure?
2. Documentation:
   • If I’m missing documentation on these changes, could someone point me to the appropriate guide or resources?
3. Integration:
   • Is there a preferred workflow or best practice for integrating new layouts with the core structure?

Status

• Work in Progress (WIP): This PR is not ready for merge until I receive further guidance and adjust the file organization accordingly.

Any suggestions or pointers to the relevant documentation would be greatly appreciated. Thanks for the support and feedback!