Fix dart sass 2 migration

[ashpsl]

Key Changes

1. Vendor Dependency Updates
   Sassy-Lists Compatibility: Patching the included sassy-lists vendor files to support Dart Sass 2. This includes adding @use sass:list and updating internal function calls to be module-aware.

2. Sass Module System Migration
   Replaced @import with @use: Updated core components and settings files to use the Sass module system. This ensures better encapsulation and avoids global namespace pollution.
   Explicit Namespacing: Updated references to variables and mixins to use their respective namespaces (e.g., migrating from global access to util.rem-calc() or grid.$grid-column-count).

3. Circular Dependency Resolution
   Math & Unit Modules: Resolved a circular dependency between the math and unit utility modules.
   Improved Math Calculations: Replaced deprecated division syntax with modern math functions (e.g., math.div logic) to ensure compatibility with Dart Sass 2's strict math rules.

4. Namespace & Scoping Fixes
   Grid Module Scoping: Standardized the use of $grid-column-count within the grid modules. Fixed instances where row.$grid-column-count was incorrectly referenced instead of the local grid namespace.
   Private Variable Visibility: Refactored variables previously starting with a hyphen (e.g., $-zf-bp-value). In Dart Sass 2 modules, variables starting with - or _ are private and cannot be accessed across files or globally. These were updated to public variables where cross-module access was required.

5. Syntax Modernization
   Wrapped specific styles in nested blocks where necessary to comply with new Sass nesting and scoping rules (e.g., flex-grid-column logic).

Testing Performed

I temporarily added @include foundation-everything; to the main file and ran the build with every possible combination of parameters for the foundation-everything mixin. The project now builds with zero errors and zero deprecation warnings under Dart Sass 2.0.