docs: clarify AI writeback PR author is the GitHub App

Author: mintlify[bot]

guides/ai-agents/ai-writeback.mdx

@@ -49,6 +49,8 @@ When you ask the agent for a change that belongs in the repo, it calls a tool ca
 
 The tool call is synchronous and can take a few minutes. The agent will tell you a pull request is being prepared while it waits.
 
+Pull requests are always opened by the Lightdash GitHub App, so the PR author in GitHub appears as the app bot (for example, `lightdash-app[bot]`) regardless of who triggered the writeback. The user who asked for the change is recorded as a co-author on the commit and tracked against the PR inside Lightdash.
+
 ## Using it in chat
 
 Phrase your request as a direct change to the repo and, where possible, name the file, model, or field you want touched. The more specific you are, the more reliably the writeback agent finds the right place to edit.