refactor(Font): use pretext layout() directly in row size resolver

createFontRowSizeResolver was reaching into TextLayoutEngine, which
internally called pretext's heavy layoutWithLines and then walked
per-grapheme cursors to build chars arrays. The resolver discarded all
that work and used only totalHeight.

Replace with direct prepare + layout from @chenglou/pretext — pretext
docs explicitly recommend layout() (not layoutWithLines) for the resize
hot path: pure arithmetic on cached segment widths, no canvas calls, no
string allocations.

Test spies on TextLayoutEngine.prototype.layout migrated to vi.mock-ed
pretext layout (pretext's ESM exports are frozen — vi.spyOn fails with
"Cannot redefine property").

TextLayoutEngine marked @deprecated since it has no remaining
consumers; slated for removal after a release cycle.

src/entities/Font/lib/sizeResolver/createFontRowSizeResolver.test.ts

@@ -1,7 +1,19 @@
 // @vitest-environment jsdom
-import { TextLayoutEngine } from '$shared/lib';
 import { installCanvasMock } from '$shared/lib/helpers/__mocks__/canvas';
-import { clearCache } from '@chenglou/pretext';
+import {
+    clearCache,
+    layout,
+} from '@chenglou/pretext';
+
+// Wrap pretext's `layout` in a spy-able mock so tests can assert call counts.
+// `vi.mock` is hoisted, so the import above receives the mocked module.
+vi.mock('@chenglou/pretext', async () => {
+    const actual = await vi.importActual<typeof import('@chenglou/pretext')>('@chenglou/pretext');
+    return {
+        ...actual,
+        layout: vi.fn(actual.layout),
+    };
+});
 import {
     beforeEach,
     describe,
@@ -112,13 +124,13 @@ describe('createFontRowSizeResolver', () => {
         const { resolver } = makeResolver();
         statusMap.set('inter@400', 'loaded');
 
-        const layoutSpy = vi.spyOn(TextLayoutEngine.prototype, 'layout');
+        const layoutSpy = vi.mocked(layout);
+        layoutSpy.mockClear();
 
         resolver(0);
         resolver(0);
 
         expect(layoutSpy).toHaveBeenCalledTimes(1);
-        layoutSpy.mockRestore();
     });
 
     it('calls layout() again when containerWidth changes (cache miss)', () => {
@@ -126,14 +138,14 @@ describe('createFontRowSizeResolver', () => {
         const { resolver } = makeResolver({ getContainerWidth: () => width });
         statusMap.set('inter@400', 'loaded');
 
-        const layoutSpy = vi.spyOn(TextLayoutEngine.prototype, 'layout');
+        const layoutSpy = vi.mocked(layout);
+        layoutSpy.mockClear();
 
         resolver(0);
         width = 100;
         resolver(0);
 
         expect(layoutSpy).toHaveBeenCalledTimes(2);
-        layoutSpy.mockRestore();
     });
 
     it('returns greater height when container narrows (more wrapping)', () => {