Instruct LLM to use section comments for placement decisions

The metadata comment fields were already being passed to the LLM but
the system prompt didn't mention them. Now it explicitly tells the LLM
to pay attention to the "comment" field when choosing a section.

Author: alexeygrigorev

faq_automation/rag_agent.py

@@ -47,7 +47,7 @@
 - Do not invent unrelated content, base decisions strictly on the provided proposal and FAQ excerpts
 - When UPDATE, merge old and new answers into one, making the updated answer complete and containing all the information from both
 - When UPDATE, make sure the new question is reflective of the both new and old records
-- Carefully analyse existing sections to decide where it goes. Generic questions that don't fit any other section should go to "general"
+- Carefully analyse existing sections to decide where it goes. Pay close attention to the "comment" field in each section — it describes what kind of questions belong there. Generic questions that don't fit any other section should go to "general"
 
 Example reasoning
 - If two FAQs are semantically the same but wording differs slightly → DUPLICATE.