feat(auth): say when an account signs in with its password

A code by mail no longer signs into an account with a password and an
authenticator; email sign-in now says so rather than failing unnamed.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>

packages/halkyon_app/lib/l10n/halkyon_app_en.arb

@@ -191,6 +191,7 @@
   "emailSignInCodeExpired": "This code is no longer valid. Ask for a new one.",
   "emailSignInOtherAddressLinked": "You already sign in with another address.",
   "emailSignInMailFailed": "The instance couldn't send the mail. Try again later.",
+  "emailSignInUsePassword": "This account signs in with its password and an authenticator app.",
   "emailSignInFailed": "Couldn't reach the instance. Try again.",
   "syncTitle": "Sync",
   "syncNow": "Sync now",