refactor(typography): lazy getTypographySettingsStore + fix effect leak

Convert the eager typographySettingsStore singleton to getTypographySettingsStore()
(+ __resetTypographySettingsStore for tests) and update barrels and consumers
(TypographyMenu, FontSampler, SampleList, ComparisonView Line/SliderArea,
comparisonStore + its mock).

Fix a latent leak while here: the store ran $effect.root and discarded the
returned cleanup, so its storage-sync effects outlived every instance. Capture
the disposer and expose destroy(), which __reset now calls.

src/features/DisplayFont/ui/FontSampler/FontSampler.svelte

@@ -9,7 +9,7 @@ import {
     type FontLoadStatus,
     type UnifiedFont,
 } from '$entities/Font';
-import { typographySettingsStore } from '$features/AdjustTypography/model';
+import { getTypographySettingsStore } from '$features/AdjustTypography/model';
 import {
     Badge,
     ContentEditable,
@@ -43,6 +43,8 @@ interface Props {
 
 let { font, status, text = $bindable(), index = 0 }: Props = $props();
 
+const typographySettingsStore = getTypographySettingsStore();
+
 // Extract provider badge with fallback
 const providerBadge = $derived(
     font.providerBadge