feat: add new dashboard components and enhance UI

- Introduced new CSS variables for light theme in `globals.css` to improve visual consistency.
- Replaced `Card` component with `StatCard`, `ProgressBar`, and `MetricCard` in `DashboardStats`, `ProductivityAnalytics`, and `RecentTasks` for better modularity and reusability.
- Updated `QuickActions` to use `ActionCard` for a more cohesive design.
- Enhanced `Badge` and `Button` components with new variants for improved styling options.
- Added new UI showcase section in `UIShowcaseClient` to demonstrate the new dashboard components.

src/components/ui/Button.tsx

@@ -2,7 +2,7 @@ import { ButtonHTMLAttributes, forwardRef } from 'react';
 import { cn } from '@/lib/utils';
 
 interface ButtonProps extends ButtonHTMLAttributes<HTMLButtonElement> {
-  variant?: 'primary' | 'secondary' | 'ghost' | 'destructive' | 'success' | 'selected';
+  variant?: 'primary' | 'secondary' | 'ghost' | 'destructive' | 'success' | 'selected' | 'danger';
   size?: 'sm' | 'md' | 'lg';
 }
 
@@ -14,7 +14,8 @@ const Button = forwardRef<HTMLButtonElement, ButtonProps>(
       ghost: 'text-[var(--foreground)] hover:bg-[var(--card-hover)]',
       destructive: 'bg-[var(--destructive)] text-white hover:bg-[color-mix(in_srgb,var(--destructive)_90%,transparent)]',
       success: 'bg-[var(--success)] text-white hover:bg-[color-mix(in_srgb,var(--success)_90%,transparent)]',
-      selected: 'bg-[color-mix(in_srgb,var(--primary)_15%,transparent)] text-[var(--foreground)] border border-[var(--primary)] hover:bg-[color-mix(in_srgb,var(--primary)_20%,transparent)]'
+      selected: 'bg-[color-mix(in_srgb,var(--primary)_15%,transparent)] text-[var(--foreground)] border border-[var(--primary)] hover:bg-[color-mix(in_srgb,var(--primary)_20%,transparent)]',
+      danger: 'bg-[var(--destructive)] text-white hover:bg-[color-mix(in_srgb,var(--destructive)_90%,transparent)]'
     };
 
     const sizes = {