Add ERI server assistant (#231)

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

@@ -0,0 +1,16 @@
+namespace AIStudio.Assistants.ERI;
+
+public static class AllowedLLMProvidersExtensions
+{
+    public static string Description(this AllowedLLMProviders provider)
+    {
+        return provider switch
+        {
+            AllowedLLMProviders.NONE => "Please select what kind of LLM provider are allowed for this data source",
+            AllowedLLMProviders.ANY => "Any LLM provider is allowed: users might choose a cloud-based or a self-hosted provider",
+            AllowedLLMProviders.SELF_HOSTED => "Self-hosted LLM providers are allowed: users cannot choose any cloud-based provider",
+            
+            _ => "Unknown option was selected"
+        };
+    }
+}