Initial Blazor Web App template

Rider-generated Blazor Web App (net10.0, interactive render mode None,
no auth scaffold, no sample pages). Includes Rider auto-formatting.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Elternbeirat.Web/Components/Pages/Error.razor

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+@page "/Error"
+@using System.Diagnostics
+
+<PageTitle>Error</PageTitle>
+
+<h1 class="text-danger">Error.</h1>
+<h2 class="text-danger">An error occurred while processing your request.</h2>
+
+@if (ShowRequestId)
+{
+    <p>
+        <strong>Request ID:</strong> <code>@RequestId</code>
+    </p>
+}
+
+<h3>Development Mode</h3>
+<p>
+    Swapping to <strong>Development</strong> environment will display more detailed information about the error that occurred.
+</p>
+<p>
+    <strong>The Development environment shouldn't be enabled for deployed applications.</strong>
+    It can result in displaying sensitive information from exceptions to end users.
+    For local debugging, enable the <strong>Development</strong> environment by setting the <strong>ASPNETCORE_ENVIRONMENT</strong> environment variable to <strong>Development</strong>
+    and restarting the app.
+</p>
+
+@code{
+    [CascadingParameter] private HttpContext? HttpContext { get; set; }
+
+    private string? RequestId { get; set; }
+    private bool ShowRequestId => !string.IsNullOrEmpty(RequestId);
+
+    protected override void OnInitialized() =>
+        RequestId = Activity.Current?.Id ?? HttpContext?.TraceIdentifier;
+
+}

Elternbeirat.Web/Components/Pages/Home.razor

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+@page "/"
+
+<PageTitle>Home</PageTitle>
+
+<h1>Hello, world!</h1>
+
+Welcome to your new app.

Elternbeirat.Web/Components/Pages/NotFound.razor

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+@page "/not-found"
+@layout MainLayout
+
+<h3>Not Found</h3>
+<p>Sorry, the content you are looking for does not exist.</p>