test: assert no indexable route starts with api/ prefix

Replace specific controller-name substring checks with a single assertion
that no route starts with 'api/' -- matches the actual filter behavior and
catches any future API controller added outside those specific names.

Author: BenjaminMichaelis

EssentialCSharp.Web.Tests/RouteConfigurationServiceTests.cs

@@ -44,13 +44,9 @@ public async Task GetIndexableRoutes_ShouldExcludeApiControllerRoutes()
             return routeConfigurationService.GetIndexableRoutes().ToList();
         });
 
-        // Assert - API routes should NOT be included
-        await Assert.That(routes).DoesNotContain(route => 
-            route.Contains("api/chat", StringComparison.OrdinalIgnoreCase));
-        await Assert.That(routes).DoesNotContain(route => 
-            route.Contains("api/listingsourcecode", StringComparison.OrdinalIgnoreCase));
-        await Assert.That(routes).DoesNotContain(route => 
-            route.Contains("api/mcptoken", StringComparison.OrdinalIgnoreCase));
+        // Assert - no indexable route should start with api/ (matches the actual filter behavior)
+        await Assert.That(routes).DoesNotContain(route =>
+            route.StartsWith("api/", StringComparison.OrdinalIgnoreCase));
     }
 
     [Test]