Summary
Add two user-selectable scroll profiles in Settings → General → Browsing → Smooth Scrolling:
Optionally include an in-UI “Test Smooth Scrolling” pane for instant preview.
Current Defaults (Smooth Scrolling = On): New Name: Smooth Scrolling (Default)
Profile 2: Smooth Scrolling (High-Refresh Display)
Designed for 120 Hz+ panels
Optional: Built-In Scroll Test
Add a “Preview Smooth Scrolling” section that renders a quick requestAnimationFrame scroll demo at the selected profile settings. This lets users verify smoothness on their own hardware before closing Settings.