Fix: Use proper @use syntax with wildcard namespace for bootstrap import

The previous @use directive without proper webpack module resolution wasn't working.
This update keeps the `~` prefix for webpack and uses `as *` to make all bootstrap
utilities available in the global scope, similar to the original @import behavior.

Author: phavekes

assets/scss/application.scss

@@ -1,7 +1,8 @@
 @charset "utf-8";
 
+@use "sass:math" as math;
+@use "~bootstrap" as *;
 @use "vars";
-@use "bootstrap";
 
 .nav-header {
   padding-bottom: 9px;