feat(profile): account-deletion flow + terminal deleted screen

Profile gains a Delete-account control (durable accounts) opening a step-up dialog: a
mailed code for an email account, or the typed DELETE phrase for a platform-only one.
On success the app swaps to a terminal AccountDeleted screen ('Учётная запись удалена')
with a Close that closes the host Mini App (telegramClose / vkClose; web = no close).
Wires deleteRequest/deleteConfirm through client/transport/mock/codec; ru/en i18n;
codec wire test + Chromium/WebKit e2e.

ui/src/lib/i18n/en.ts

@@ -188,6 +188,15 @@ export const en = {
   'profile.unlinked': 'Account unlinked.',
   'profile.unlinkTitle': 'Unlink account?',
   'profile.unlinkBody': 'Remove {provider} as a sign-in method? You can link it again later.',
+  'profile.deleteAccount': 'Delete account',
+  'profile.deleteTitle': 'Delete your account?',
+  'profile.deleteWarn': 'This removes your account and frees your sign-in methods. It cannot be undone.',
+  'profile.deleteEmailPrompt': 'We sent a code to your email. Enter it to delete your account.',
+  'profile.deletePhrasePrompt': 'Type DELETE to confirm.',
+  'profile.deletePhrasePlaceholder': 'DELETE',
+  'profile.deleteConfirm': 'Delete permanently',
+  'deleted.title': 'Account deleted',
+  'deleted.body': 'Your account has been removed. Reopening the app just creates a new account.',
 
   'settings.title': 'Settings',
   'settings.theme': 'Theme',