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_de.dart

@@ -800,4 +800,11 @@ class HalkyonAppLocalizationsDe extends HalkyonAppLocalizations {
   @override
   String get passwordAddressUnknown =>
       'Dieses Gerät kennt die Adresse deines Kontos nicht, die das braucht. Melde dich ab und wieder mit deiner Adresse und deinem Passwort an.';
+
+  @override
+  String get passwordDeleteIntroByMail =>
+      'Dein Konto wird mit allem darin gelöscht, in jedem Dienst dieser Instanz. Seine Authenticator-App ist nicht eingerichtet, daher bestätigt es ein Code per E-Mail: Gib dein Passwort ein, dann den Code, den wir an deine Adresse schicken.';
+
+  @override
+  String get passwordDeleteSendCode => 'Code per E-Mail schicken';
 }