fix(router): ship audit bundle frontdoor cutover

src/Router/StellaOps.Gateway.WebService/Configuration/GatewayOptionsValidator.cs

@@ -45,6 +45,8 @@ public static class GatewayOptionsValidator
 
     private static void ValidateRoutes(List<StellaOpsRoute> routes)
     {
+        var exactPathIndices = new Dictionary<string, int>(StringComparer.OrdinalIgnoreCase);
+
         for (var i = 0; i < routes.Count; i++)
         {
             var route = routes[i];
@@ -66,6 +68,17 @@ public static class GatewayOptionsValidator
                     throw new InvalidOperationException($"{prefix}: Path is not a valid regex pattern: {ex.Message}");
                 }
             }
+            else
+            {
+                var normalizedPath = NormalizePath(route.Path);
+                if (exactPathIndices.TryGetValue(normalizedPath, out var existingIndex))
+                {
+                    throw new InvalidOperationException(
+                        $"{prefix}: Duplicate route path '{normalizedPath}' already defined by Route[{existingIndex}].");
+                }
+
+                exactPathIndices[normalizedPath] = i;
+            }
 
             switch (route.Type)
             {
@@ -124,4 +137,16 @@ public static class GatewayOptionsValidator
             }
         }
     }
+
+    private static string NormalizePath(string value)
+    {
+        var normalized = value.Trim();
+        if (!normalized.StartsWith('/'))
+        {
+            normalized = "/" + normalized;
+        }
+
+        normalized = normalized.TrimEnd('/');
+        return string.IsNullOrEmpty(normalized) ? "/" : normalized;
+    }
 }