refactor(ComparisonView): unify pretext font string generation with a utility function

src/widgets/ComparisonView/ui/SliderArea/SliderArea.svelte

@@ -22,6 +22,7 @@ import clsx from 'clsx';
 import { getContext } from 'svelte';
 import { Spring } from 'svelte/motion';
 import { fade } from 'svelte/transition';
+import { getPretextFontString } from '../../lib';
 import { comparisonStore } from '../../model';
 import Character from '../Character/Character.svelte';
 import Line from '../Line/Line.svelte';
@@ -132,8 +133,8 @@ $effect(() => {
 
     if (container && fontA && fontB) {
         // PRETEXT API strings: "weight sizepx family"
-        const fontAStr = `${_weight} ${_size}px "${fontA.name}"`;
-        const fontBStr = `${_weight} ${_size}px "${fontB.name}"`;
+        const fontAStr = getPretextFontString(_weight, _size, fontA.name);
+        const fontBStr = getPretextFontString(_weight, _size, fontB.name);
 
         // Use offsetWidth to avoid transform scaling issues
         const width = container.offsetWidth;
@@ -165,8 +166,8 @@ $effect(() => {
             containerWidth = width;
             layoutResult = comparisonEngine.layout(
                 comparisonStore.text,
-                `${typography.weight} ${typography.renderedSize}px "${fontA.name}"`,
-                `${typography.weight} ${typography.renderedSize}px "${fontB.name}"`,
+                getPretextFontString(typography.weight, typography.renderedSize, fontA.name),
+                getPretextFontString(typography.weight, typography.renderedSize, fontB.name),
                 width - padding,
                 typography.renderedSize * typography.height,
                 typography.spacing,