fix(mobile): show feature-flag row state in the app language

apps/mobile/src/components/feature-flags-section.tsx

@@ -11,11 +11,11 @@ import { type FeatureFlagStatus, useFeatureFlagStatuses } from '@/lib/analytics/
  * predates the flag's minimum app version. Read-only: flags are controlled in
  * PostHog. Renders nothing when `__DEV__` is false.
  *
- * Each row reads `<value> · <source> · <version relation>`, e.g.
+ * Each row reads `<value> · <source> · <relation>`, e.g.
  * `Enabled · remote · ≥ 1.0.4`: the value the UI acts on, whether it came
- * from PostHog or the flag's default, and the gate that decided. The source
- * and relation copy is technical notation (see the i18n allowlist); the
- * translated part is the value word and the section header.
+ * from PostHog or the flag's default, and the gate that decided. Every word
+ * comes from the catalog — the value, the source and the state; only the
+ * `{{min}}`/`v{{version}}` versions and the `≥`/`<` operators are notation.
  */
 function FlagRow({ status }: { status: FeatureFlagStatus }) {
   const { t } = useTranslation();

apps/mobile/src/i18n/feature-flag-copy.test.ts

@@ -0,0 +1,56 @@
+import { describe, expect, it } from 'vitest';
+
+import { CATALOG_LOADERS } from './catalogs';
+import { SUPPORTED_LANGUAGES, type SupportedLanguage } from './languages';
+
+/**
+ * The Preferences feature-flag rows name the source and state of the value the
+ * build acted on: `remote` or `default`, and the version gate. The row prefix
+ * (`common.enabled`) is translated, but the source and state words shipped as
+ * English notation in every catalog, so the otherwise Arabic screen read
+ * `default · not loaded` beside the localized value word.
+ *
+ * Key parity only fails when a key is English in EVERY locale, so a single
+ * catalog left in English passes `catalog-parity.test.ts` and still shows the
+ * English copy on the device. That is the half this test owns, and it is the
+ * rule `label-reference.test.ts` already applies to the PR-comment copy. The
+ * assertions below fire on every catalog that still ships English: a catalog
+ * that is missing a key resolves to English at runtime, so it fails here too.
+ */
+const FEATURE_FLAG_COPY_KEYS = [
+  'preferences.featureFlagApplied',
+  'preferences.featureFlagSkipped',
+  'preferences.featureFlagNotLoaded',
+] as const;
+
+/** The string a catalog itself ships for a dotted key, or undefined. */
+function catalogValue(tag: SupportedLanguage, key: string): string | undefined {
+  let node: unknown = CATALOG_LOADERS[tag]();
+  for (const part of key.split('.')) {
+    if (typeof node !== 'object' || node === null) {
+      return undefined;
+    }
+    node = (node as Record<string, unknown>)[part];
+  }
+  return typeof node === 'string' ? node : undefined;
+}
+
+describe('feature-flag row copy', () => {
+  it('defines every key in English', () => {
+    for (const key of FEATURE_FLAG_COPY_KEYS) {
+      expect(catalogValue('en', key), `en.json is missing ${key}`).toBeTruthy();
+    }
+  });
+
+  it.each(SUPPORTED_LANGUAGES.filter(tag => tag !== 'en'))(
+    '%s ships its own feature-flag copy',
+    tag => {
+      for (const key of FEATURE_FLAG_COPY_KEYS) {
+        const value = catalogValue(tag, key);
+        expect(value, `${tag} ${key} is missing`).toBeTruthy();
+        expect(value?.trim(), `${tag} ${key} is empty`).toBeTruthy();
+        expect(value, `${tag} ${key} is the English copy`).not.toBe(catalogValue('en', key));
+      }
+    }
+  );
+});