Refactors UI components with new card header structure

Replaces `swp-section-label` with standardized `swp-card-header` and `swp-card-title`

Improves component consistency across multiple features:
- Adds structured card headers
- Introduces more semantic HTML elements
- Enhances layout and readability of card components

Updates CSS and component styles to support new structure

PlanTempus.Application/Features/Employees/Components/EmployeeDetailStats/Default.cshtml

@@ -2,7 +2,9 @@
 
 <swp-detail-grid>
     <swp-card>
-        <swp-section-label>@Model.LabelPerformance</swp-section-label>
+        <swp-card-header>
+            <swp-card-title>@Model.LabelPerformance</swp-card-title>
+        </swp-card-header>
         <swp-stats-row>
             <swp-stat-card class="teal">
                 <swp-stat-value>@Model.BookingsThisYear</swp-stat-value>
@@ -24,7 +26,9 @@
     </swp-card>
 
     <swp-card class="stats-bookings">
-        <swp-section-label>@Model.LabelCompletedBookings</swp-section-label>
+        <swp-card-header>
+            <swp-card-title>@Model.LabelCompletedBookings</swp-card-title>
+        </swp-card-header>
         <swp-data-table>
             <swp-data-table-header>
                 <swp-data-table-cell>@Model.LabelDate</swp-data-table-cell>