chore: upgrade i18next 26, prettier 3, fontsource-variable, domhandler 6, lint-staged 17

- i18next 23->26 + react-i18next 15->17
- prettier 2->3, reformat all files
- replace @fontsource/inter with @fontsource-variable/inter 5, update import path
- domhandler 5->6 (aligns with transitive deps)
- lint-staged 16->17

src/app/utils/matrix-crypto.ts

@@ -3,7 +3,7 @@ import { CryptoApi } from 'matrix-js-sdk/lib/crypto-api';
 export const verifiedDevice = async (
   api: CryptoApi,
   userId: string,
-  deviceId: string
+  deviceId: string,
 ): Promise<boolean | null> => {
   const status = await api.getDeviceVerificationStatus(userId, deviceId);