Add comprehensive semantic design token system

Implement complete semantic layer for all design tokens including typography, spacing, motion, colors, borders, shadows, z-index, opacity, and glass effects. Each semantic token maps base design tokens to contextual usage patterns for improved maintainability and developer experience.

Features:
- Complete semantic typography system with font weights, sizes, line heights, and letter spacing
- Comprehensive spacing tokens for components, layouts, and interactions
- Full motion system with durations, easing, transitions, and hover transforms
- Semantic color system with individual access to all Material Design 3 colors
- Border tokens with widths, radius, and styles for all use cases
- Shadow system including standard and AI-themed shadows
- Z-index layering system for proper stacking context
- Opacity tokens for transparency and visibility states
- Glass morphism tokens with blur, opacity, and theming support

All semantic tokens provide direct access to base token values while offering meaningful contextual aliases for common UI patterns.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

projects/shared-ui/src/styles/commons/layouts/_index.scss

@@ -0,0 +1,13 @@
+// ==========================================================================
+// COMMONS LAYOUTS INDEX
+// ==========================================================================
+// Import all layout-related commons files
+// Theme-agnostic structural definitions
+// ==========================================================================
+
+@import 'dashboard-layouts';
+@import 'grid-systems';
+@import 'content-containers';
+@import 'page-templates';
+@import 'responsive-layouts';
+@import 'layout-system';