feat(app-expo): tiered large-text presets with English-friendly default

Replace the boolean large-text flag with three global typography tiers,
defaulting new installs to the smallest tier when English is in effect
while preserving legacy storage and Chinese defaults. Add a profile
sub-screen to pick the tier and unit tests for storage resolution.

Co-authored-by: Cursor <cursoragent@cursor.com>

app-expo/tests/core/settings/app-settings-large-text.test.ts

@@ -0,0 +1,31 @@
+import {
+  computeLargeTextLevelFromStorage,
+  defaultLargeTextLevelForLanguage,
+} from '@/core/settings/app-settings';
+
+describe('defaultLargeTextLevelForLanguage', () => {
+  it('uses level 0 for English', () => {
+    expect(defaultLargeTextLevelForLanguage('en')).toBe(0);
+  });
+
+  it('uses level 1 for Chinese', () => {
+    expect(defaultLargeTextLevelForLanguage('zh')).toBe(1);
+  });
+});
+
+describe('computeLargeTextLevelFromStorage', () => {
+  it('prefers valid level key when present', () => {
+    expect(computeLargeTextLevelFromStorage('2', 'false', 'en')).toBe(2);
+    expect(computeLargeTextLevelFromStorage('0', 'true', 'zh')).toBe(0);
+  });
+
+  it('ignores invalid level key and uses legacy', () => {
+    expect(computeLargeTextLevelFromStorage('9', 'true', 'en')).toBe(1);
+    expect(computeLargeTextLevelFromStorage('', 'false', 'zh')).toBe(0);
+  });
+
+  it('uses language default when no usable values', () => {
+    expect(computeLargeTextLevelFromStorage(null, null, 'en')).toBe(0);
+    expect(computeLargeTextLevelFromStorage('', '', 'zh')).toBe(1);
+  });
+});