Material Able-inspired Bootstrap 4 UI patch for IMEAL CRUD

Files included:
- header.php
- footer.php
- assets/css/imeal-material-able.css
- assets/js/imeal-material-able.js

How to apply:
1. Back up your current files first.
2. Copy header.php and footer.php to your main IMEAL CRUD folder.
3. Copy the assets folder to your main IMEAL CRUD folder.
4. Do not import any SQL; this is a UI-only patch.

Notes:
- This does not use paid Material Able template files.
- It uses Bootstrap 4.6 via CDN and a custom Material Able-inspired layout.
- Quick Add links are not included.
- The left menu is compact and grouped.
