Automated system messages with <system-reminder> tags were incorrectly
triggering [search-mode], [analyze-mode], and other keyword modes when
they contained words like "search", "find", "explore", etc.
Changes:
- Add removeSystemReminders() to strip <system-reminder> content before keyword detection
- Add hasSystemReminder() utility function
- Update keyword-detector to clean text before pattern matching
- Add comprehensive test coverage for system-reminder filtering
Fixes issue where automated system notifications caused agents to
incorrectly enter MAXIMUM SEARCH EFFORT mode.
Co-authored-by: TheEpTic <git@eptic.me>
