fix(radius): bump shared RADIUS_PRESETS so S/M/L are visible on real elements

The actual radius picker shown to users for images, sections, and
containers comes from ImageStylePanel etc. via the shared
RADIUS_PRESETS — not from each component's own settings panel. Earlier
fix only bumped ImageBlock's local scale, which is a different control.

Bump shared scale: S=8px, M=16px, L=32px, Full=9999px (unchanged).
Existing saved sites are unaffected — only future preset clicks pick
up the new values.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

craft/src/constants/presets.ts

@@ -58,9 +58,9 @@ export const SPACING_PRESETS = [
 
 export const RADIUS_PRESETS = [
   { label: 'None', value: '0' },
-  { label: 'S', value: '4px' },
-  { label: 'M', value: '8px' },
-  { label: 'L', value: '16px' },
+  { label: 'S', value: '8px' },
+  { label: 'M', value: '16px' },
+  { label: 'L', value: '32px' },
   { label: 'Full', value: '9999px' },
 ];