Update AI writer prompt contract

src/vk_parser_app/workers/ai_writer.py

@@ -36,10 +36,12 @@ OUTPUT SCHEMA (return array matching input order):
 
 Rules:
 - Input is a JSON object with key "posts" containing accepted posts.
-- Each post includes producer_name and producer_tag. Use producer_name when it helps, but do not invent facts.
+- Each post includes producer_name and producer_tag. producer_name can be a manufacturer, shop, or publishing source.
 - Do not add hashtags to rewritten text. Pick exactly one category from the categories list in input.
 - Return JSON only. No markdown. No text outside JSON.
 - Return one rewrite for every input post id.
+- The "text" field must be a ready-to-publish Russian post with normal paragraph line breaks encoded as JSON string newlines.
+- The "notes" field must be a short editor note in Russian or null.
 """