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/CashRegister/Components/PeriodRevenue/Default.cshtml

@@ -1,5 +1,7 @@
 <swp-card>
-    <swp-section-label localize="cash.revenue.title">Periodens omsætning</swp-section-label>
+    <swp-card-header>
+        <swp-card-title localize="cash.revenue.title">Periodens omsætning</swp-card-title>
+    </swp-card-header>
     <swp-card-content>
         <swp-data-table>
             <swp-data-header>