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/App.razor

@@ -0,0 +1,20 @@
+<!DOCTYPE html>
+<html lang="en">
+
+<head>
+    <meta charset="utf-8"/>
+    <meta name="viewport" content="width=device-width, initial-scale=1.0"/>
+    <base href="/"/>
+    <ResourcePreloader/>
+    <link rel="stylesheet" href="@Assets["app.css"]"/>
+    <link rel="stylesheet" href="@Assets["Elternbeirat.Web.styles.css"]"/>
+    <ImportMap/>
+    <HeadOutlet/>
+</head>
+
+<body>
+<Routes/>
+<script src="@Assets["_framework/blazor.web.js"]"></script>
+</body>
+
+</html>