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/App.svelte

@@ -20,6 +20,7 @@
   import CommsHub from './game/CommsHub.svelte';
   import Feedback from './screens/Feedback.svelte';
   import Blocked from './screens/Blocked.svelte';
+  import AccountDeleted from './screens/AccountDeleted.svelte';
   import BootError from './screens/BootError.svelte';
   import TelegramLaunchError from './screens/TelegramLaunchError.svelte';
 
@@ -83,6 +84,8 @@
   <!-- A Mini App launch that failed to authenticate (e.g. the backend was down mid-deploy):
        show the retry screen instead of falling back to the web login. -->
   <BootError />
+{:else if app.accountDeleted}
+  <AccountDeleted />
 {:else if app.blocked}
   <Blocked />
 {:else}