Fix ai-controllers.json format

- Change from object to simple array format
- The mention detector expects a plain array of usernames
- Fixes TypeError: allowedUsers.includes is not a function

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: justaddcoffee

.github/ai-controllers.json

@@ -1,4 +1 @@
-{
-  "controllers": ["jtr4v", "justaddcoffee"],
-  "fallback_controllers": ["jtr4v"]
-}
+["jtr4v", "justaddcoffee"]