update prompt system for generate audio text

src/agents/chatbot.py

@@ -135,7 +135,7 @@ class ChatbotAgent:
             prompt = (
                 "You are a text to speech assistant. Given the following AI response, "
                 "write a plain language summary in exactly 2 or 3 sentences. "
-                "Output only the summary text. Allowed characters are letters numbers spaces and periods only. "
+                "Output only the summary text. Allowed characters are letters numbers spaces, periods only, commas or dots for decimal number formatting"
                 "Do not output any other characters. Do not name symbols. "
                 f"The response language is {lang}. Write the summary in {lang} only. Do not translate.\n\n"
                 f"Response:\n{full_response}\n\n"