feat(ui): one-tap confirm deeplink screen + client language

Add the /confirm/<token> SPA route and Confirm screen: a prefetch-safe button
POSTs the token via a new confirmEmailLink RPC (client/transport/mock/codec +
ConfirmLinkResult model). A login adopts the minted session and enters the app; a
link shows confirmed / merge-in-the-app; an invalid or expired token asks for a new
code. Exempt /confirm from the no-session /login redirect. Forward the client
locale on the email request (authEmailRequest gains language → app.locale) so a
fresh web login email is localised. Handle the new 'profile' live-event sub-kind by
re-fetching the profile, so a link confirmed in another browser reflects in-app at
once. i18n en+ru.

ui/src/lib/i18n/en.ts

@@ -36,6 +36,12 @@ export const en = {
   'login.sendCode': 'Send code',
   'login.codePlaceholder': '6-digit code',
   'login.signIn': 'Sign in',
+  'confirm.prompt': 'Confirm your email to finish.',
+  'confirm.action': 'Confirm',
+  'confirm.linked': 'Email confirmed.',
+  'confirm.merge': 'Almost done — finish the merge in the app.',
+  'confirm.close': 'You can close this window and return to the game.',
+  'confirm.expired': 'This link is invalid or has expired. Request a new code.',
   'login.codeSent': 'We sent a code to {email}.',
 
   'lobby.activeGames': 'Active games',