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/client.ts

@@ -20,6 +20,7 @@ import type {
   HintResult,
   Invitation,
   InvitationSettings,
+  ConfirmLinkResult,
   LinkResult,
   MatchResult,
   MoveResult,
@@ -64,8 +65,11 @@ export interface GatewayClient {
    *  cosmetic seed for a brand-new account). */
   authVK(params: string, displayName: string): Promise<Session>;
   authGuest(locale?: string): Promise<Session>;
-  authEmailRequest(email: string): Promise<void>;
+  authEmailRequest(email: string, language: string): Promise<void>;
   authEmailLogin(email: string, code: string): Promise<Session>;
+  /** Confirm a one-tap email deeplink token: a login returns a session to adopt; a
+   *  link returns a status ('confirmed' | 'merge_required'). */
+  confirmEmailLink(token: string): Promise<ConfirmLinkResult>;
 
   // --- profile / lists ---
   profileGet(): Promise<Profile>;