Line-width guide keeps returning to default position with editor-config plugin active

## Steps to Reproduce

0. Make sure editor-config plugin is active
1. Turn on line-width guide in preferences. Guide appears at 80 cols.
2. Change from default of 80 to e.g. 120. Guide moves to 120 cols.
3. Close preferences - the guide returns to 80 cols
4. Press `=` to set font size. Guide changes to 120
5. Focus another window. Guide stays at 120
6. Refocus the document. Guide returns to 80
7. Turn off editor-config plugin. Guide returns to and stays at 120

## Expected Behavior
The guide always shows at the position set by the user in Preferences

### Logs

## Platform Information
Elementary 6.0 daily.

Reproduce the issue with the editor-config plugin active, then inspect the line-width guide preference and the plugin behavior around preference closure, font-size changes, and document focus. The work is done when a user-set guide position remains unchanged through those actions, including while the plugin is active.

Written by the indexing model from the issue text.