The Help menu lived in a separate Menubar from the Settings/Workers/
Folders/Logs group, so melt-ui's hover-to-switch logic (which only
spans menus within the same Menubar) did not close the Help popup
when the cursor moved to a sibling group, causing menus to stack.
Merge both bottom Menubars into a single Menubar, wrapping each
group in its own flex container to preserve the visual spacing.
Fixes WIN-1993
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>