Adds Online Booking configuration and preview components

Introduces comprehensive online booking feature with:
- Localization support for booking settings
- ViewComponents for booking URL, settings, company info, hours, and preview
- Responsive preview with device toggle functionality
- Integrated with settings page and translation files

Enhances application's online booking configuration interface

PlanTempus.Application/Features/OnlineBooking/Pages/Index.cshtml

@@ -0,0 +1,42 @@
+@page "/online-booking"
+@model PlanTempus.Application.Features.OnlineBooking.Pages.IndexModel
+@{
+    ViewData["Title"] = "Online Booking";
+}
+
+<swp-sticky-header>
+    <swp-header-content>
+        <swp-page-header>
+            <swp-page-title>
+                <h1 localize="onlineBooking.title">Online Booking</h1>
+                <p localize="onlineBooking.subtitle">Konfigurer og preview din booking-side</p>
+            </swp-page-title>
+            <swp-page-actions>
+                <swp-status-indicator data-active="true">
+                    <i class="ph ph-check-circle icon"></i>
+                    <span localize="onlineBooking.status.active">Aktiv</span>
+                </swp-status-indicator>
+            </swp-page-actions>
+        </swp-page-header>
+    </swp-header-content>
+</swp-sticky-header>
+
+<swp-page-container>
+    <swp-online-booking-layout>
+        <!-- Column 1: Settings -->
+        <swp-online-booking-settings>
+            @await Component.InvokeAsync("OnlineBookingUrl")
+            @await Component.InvokeAsync("OnlineBookingSettings")
+            @await Component.InvokeAsync("OnlineBookingCompany")
+            @await Component.InvokeAsync("OnlineBookingHours")
+
+            <swp-all-settings-link href="/indstillinger">
+                <span localize="onlineBooking.allSettings">Alle indstillinger</span>
+                <i class="ph ph-arrow-right"></i>
+            </swp-all-settings-link>
+        </swp-online-booking-settings>
+
+        <!-- Column 2: Preview -->
+        @await Component.InvokeAsync("OnlineBookingPreview")
+    </swp-online-booking-layout>
+</swp-page-container>

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

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+using Microsoft.AspNetCore.Mvc.RazorPages;
+
+namespace PlanTempus.Application.Features.OnlineBooking.Pages;
+
+public class IndexModel : PageModel
+{
+    public void OnGet()
+    {
+    }
+}