Accessibility for QML components

[PyXiion]

Origin of idea

Origin of idea
No QML item sets Accessible.role, Accessible.name, or Accessible.description. Screen reader users get no context. No high-contrast mode. Keyboard navigation is only partial (ModList has arrows, nothing else).

Suggestion / proposed solution

1. Add Accessible.role, .name, .description to all interactive QML items (buttons, checkboxes, list items, sidebar entries)
2. Audit keyboard navigation: every interactive element must be reachable via Tab, activated via Enter/Space
3. Add visible focus indicators (custom or rely on Qt style)
4. Support OS high-contrast / increase-font-size accessibility settings
5. Add "Announce notifications" option to route toast messages to screen reader

Alternatives considered

No response

Additional context

Qt Quick accessibility docs: https://doc.qt.io/qt-6/qtquick-accessibility.html. All interactive QML is in 5 files.