Adds Kasse (Cash Register) module and related components

Introduces comprehensive cash management functionality with multiple view components for tracking daily transactions, filtering, and reconciliation

Implements:
- Cash calculation and difference tracking
- Dynamic tab switching
- Checkbox selection and row expansion
- Date filtering and approval mechanisms

PlanTempus.Application/Features/Kasse/Pages/Index.cshtml.cs

@@ -0,0 +1,10 @@
+using Microsoft.AspNetCore.Mvc.RazorPages;
+
+namespace PlanTempus.Application.Features.Kasse.Pages;
+
+public class IndexModel : PageModel
+{
+    public void OnGet()
+    {
+    }
+}