Restructure into feature folders with code-behind and scoped CSS

Elternbeirat.Web/Features/Posts/PostDetail.razor.cs

@@ -0,0 +1,31 @@
+using System.Globalization;
+using Elternbeirat.Web.Services;
+using Microsoft.AspNetCore.Components;
+using Microsoft.AspNetCore.Http;
+
+namespace Elternbeirat.Web.Features.Posts;
+
+public partial class PostDetail
+{
+    private static readonly CultureInfo German = CultureInfo.GetCultureInfo("de-DE");
+
+    [Parameter]
+    public string Slug { get; set; } = "";
+
+    private Post? _post;
+
+    protected override void OnParametersSet()
+    {
+        _post = PostService.Find(Slug);
+
+        // Unknown slug -> 404, so UseStatusCodePagesWithReExecute serves the
+        // /not-found page instead of an empty 200 response.
+        if (_post is null && HttpContext is not null)
+        {
+            HttpContext.Response.StatusCode = StatusCodes.Status404NotFound;
+        }
+    }
+
+    [CascadingParameter]
+    private HttpContext? HttpContext { get; set; }
+}