feat: guest purchase cabinet credentials UI

- CabinetCredentialsState with copyable email/password fields
- Auto-login via JWT token with checkAdminStatus
- /auto-login route with ErrorBoundary and no-referrer meta
- Narrowed contact_type to 'email' | 'telegram' | null
- Disabled button styling for PendingActivation go-to-cabinet
- i18n: added landing.copy key to all 4 locales

src/api/auth.ts

@@ -280,6 +280,12 @@ export const authApi = {
     return response.data;
   },
 
+  // Auto-login from guest purchase success page
+  autoLogin: async (token: string): Promise<AuthResponse> => {
+    const response = await apiClient.post<AuthResponse>('/cabinet/auth/login/auto', { token });
+    return response.data;
+  },
+
   // Account merge (no JWT required)
   getMergePreview: async (mergeToken: string): Promise<MergePreviewResponse> => {
     const response = await apiClient.get<MergePreviewResponse>(