Add ERI server assistant (#231)

app/MindWork AI Studio/Assistants/ERI/ERIVersionExtensions.cs

@@ -0,0 +1,27 @@
+namespace AIStudio.Assistants.ERI;
+
+public static class ERIVersionExtensions
+{
+    public static async Task<string> ReadSpecification(this ERIVersion version, HttpClient httpClient)
+    {
+        try
+        {
+            var url = version.SpecificationURL();
+            var response = await httpClient.GetAsync(url);
+            return await response.Content.ReadAsStringAsync();
+        }
+        catch
+        {
+            return string.Empty;
+        }
+    }
+    
+    public static string SpecificationURL(this ERIVersion version)
+    {
+        var nameLower = version.ToString().ToLowerInvariant();
+        var filename = $"{nameLower}.json";
+        return $"specs/eri/{filename}";
+    }
+    
+    public static bool WasSpecificationSelected(this ERIVersion version) => version != ERIVersion.NONE;
+}