fix(ci): keep mobile localization out of desktop-only test installs (#35576)

Load the Hermes plural-rules polyfill from the phone app entry instead of
mobile-i18n, and transform mobile-i18n and its catalog loader without the
Expo tsconfig in root vitest.

config/vitest.config.ts

@@ -23,7 +23,9 @@ const paletteMeasurementFile =
 const measurementFiles = [measurementFile, paletteMeasurementFile]
 const phoneContractModules = [
   'mobile/src/session/native-chat/mobile-native-chat-stream-frame.ts',
-  'mobile/src/session/mobile-native-chat-render-data.ts'
+  'mobile/src/session/mobile-native-chat-render-data.ts',
+  'mobile/src/i18n/mobile-i18n.ts',
+  'mobile/src/i18n/locale-catalog-imports.ts'
 ].map((file) => normalizePath(resolve(file)))
 const phoneContractPattern = new RegExp(
   `^(?:${phoneContractModules.map((file) => file.replace(/[.*+?^${}()|[\]\\]/g, '\\$&')).join('|')})(?:\\?.*)?$`

mobile/index.js

@@ -1,3 +1,5 @@
+// Before any module that builds i18next plural rules; kept out of mobile-i18n so desktop tests need no mobile deps.
+import './src/i18n/plural-rules-polyfill'
 // Headless notification launches do not mount the router layout.
 import './src/notifications/push-background-dismissal'
 import { loadPairedE2EENativeBindings } from './src/transport/paired-e2ee-native-bindings'

mobile/src/i18n/mobile-i18n.ts

@@ -1,4 +1,3 @@
-import './plural-rules-polyfill'
 import i18next, { type TOptions } from 'i18next'
 import { resolvePluralFamilyKey } from '../../../src/shared/i18n-plural-family'
 import { pseudoLocalizeString } from '../../../src/shared/pseudo-localization'