panels.js _autosaveAppearanceSettings (6309) + _applySavedSettingsUi (7837) read
auto_scroll_follow from a settings/body object — use !==false (default True) for
consistency with boot.js + the checkbox render, so a future partial-body refactor
can't silently default the True setting OFF. The .checked reads (6223/8170) keep !!
(a real bool).