feat(payment): add chat support discounts and gratitude

(cherry picked from commit ef9b79bc83)

src/stores/chat/chat-events.ts

@@ -28,6 +28,15 @@ export type ChatEvent =
     }
   | { type: "ChatOlderHistoryLoadFailed"; error: unknown }
   | { type: "ChatHistoryRefreshRequested" }
+  | {
+      type: "ChatCommercialMessageReceived";
+      message: {
+        messageId: string;
+        message: string;
+        characterId: string;
+        createdAt: string;
+      };
+    }
   // Chat domain events.
   | { type: "ChatSendMessage"; content: string }
   | { type: "ChatSendImage"; imageBase64: string }