repomap-auto-on

Enable automatic repo map updates. When enabled, REPOMAP.md is incrementally updated every time a file is edited.

Run this command:

touch .repomap-auto

Confirm that auto-updating is now enabled. Remind the user that REPOMAP.md must already exist (run /repomap first if it doesn't). The .repomap-auto file is a toggle — delete it to disable auto-updates.