Added a common augmentation interface & default implementation (#288)

app/MindWork AI Studio/Provider/Google/ProviderGoogle.cs

@@ -50,6 +50,7 @@ public class ProviderGoogle(ILogger logger) : BaseProvider("https://generativela
                     ChatRole.AI => "assistant",
                     ChatRole.AGENT => "assistant",
                     ChatRole.SYSTEM => "system",
+                    ChatRole.RAG => "assistant",
 
                     _ => "user",
                 },