fix(auth): an account whose second factor doesn't work deletes itself

An account whose setup never finished, or whose authenticators' reset took
effect, could not delete itself (the re-review's eighth finding): deletion
asked for a TOTP or recovery code it had no way to give. Such an account
now deletes itself with the password's proof and a code by mail to its
address asked for deleting (EmailCodePurpose.deletion, which nothing else
takes), the address checked against the account's as everywhere after the
password; an account whose second factor works still takes a code from it.
The app's deletion sheet asks for the password and mails the code there,
then takes it.

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_localizations_en.dart

@@ -783,6 +783,13 @@ class HalkyonAppLocalizationsEn extends HalkyonAppLocalizations {
   @override
   String get passwordAddressUnknown =>
       'This device doesn\'t know your account\'s address, which this takes. Sign out, then sign in again with your address and password.';
+
+  @override
+  String get passwordDeleteIntroByMail =>
+      'Your account goes with everything in it, in every service of this instance. Its authenticator isn\'t set up, so a code by mail confirms it: type your password, then the code we email to your address.';
+
+  @override
+  String get passwordDeleteSendCode => 'Email me a code';
 }
 
 /// The translations for English, as used in the United Kingdom (`en_GB`).