Add collapsible local and remote branch groups to the branch
visibility dialog, including toggle buttons and selection counts.
Introduce comprehensive dialog styling and responsive rules to match
the app UI. Opening the dialog now defaults to local open and remote
closed for faster access.
- Add CSS for branch-filter dialog layout, theming, and responsiveness
- Implement group toggles with chevrons and visible selected counts
- Default to local group open and remote group closed on dialog open
Christoph