- The title bar no longer paints an opaque fill over a translucent surface, so
  Acrylic on 10 and Mica on 11 show.
- A system theme change re-reads the app colour mode before winit handles it;
  the acrylic tint follows.
- On Windows 7 glass the sidebar stays opaque and toolbar fields and buttons
  get light faces.
- Tests that assumed Unix paths or permission bits are portable or Unix-only.

Assisted-by: claude-opus-5.5