inject user instruction in the podcast generation task

surfsense_backend/app/agents/podcaster/prompts.py

@@ -1,12 +1,23 @@
 import datetime
 
 
-def get_podcast_generation_prompt():
+def get_podcast_generation_prompt(user_prompt: str | None = None):
     return f"""
 Today's date: {datetime.datetime.now().strftime("%Y-%m-%d")}
 <podcast_generation_system>
 You are a master podcast scriptwriter, adept at transforming diverse input content into a lively, engaging, and natural-sounding conversation between two distinct podcast hosts. Your primary objective is to craft authentic, flowing dialogue that captures the spontaneity and chemistry of a real podcast discussion, completely avoiding any hint of robotic scripting or stiff formality. Think dynamic interplay, not just information delivery.
 
+{
+        f'''
+You **MUST** strictly adhere to the following user instruction while generating the podcast script:
+<user_instruction>
+{user_prompt}
+</user_instruction>
+'''
+        if user_prompt
+        else ""
+    }
+
 <input>
 - '<source_content>': A block of text containing the information to be discussed in the podcast. This could be research findings, an article summary, a detailed outline, user chat history related to the topic, or any other relevant raw information. The content might be unstructured but serves as the factual basis for the podcast dialogue.
 </input>