feat(a11y): cross-platform hardening + modal focus-trap from impeccable audit

Responsive / viewport:
- add .min-h-viewport / .h-viewport utilities (100dvh + Telegram --tg-viewport-stable-height)
- migrate min-h-screen / h-screen / 100vh across 18 files
- reveal hover-only controls on focus-within + touch (desktop nav, admin settings)
- grid breakpoints (TopUpAmount, Contests), larger touch targets, nav aria-labels

Platform routing (Telegram WebView correctness):
- clipboard -> copyToClipboard util with execCommand fallback (10 files)
- window.open -> openTelegramLink / openLink (Profile, Referral, ChannelSubscriptionScreen)
- window.confirm -> useNativeDialog (admin pages); PromoOffersSection -> useDestructiveConfirm
- window.prompt -> usePrompt / PromptDialogHost (TipTap link editors)
- ESLint no-restricted-properties guard against regressions (adapters/clipboard util exempt)

Modal accessibility:
- new useFocusTrap hook (focus trap, Esc, scroll lock, focus restore)
- role=dialog / aria-modal / focus-trap: Polls, SuccessNotificationModal, AdminPolicies,
  AdminPromoGroups, AdminCampaigns, BroadcastPreview (Telegram + Email)
- new global usePrompt store + PromptDialogHost

src/components/admin/ButtonsTab.tsx

@@ -11,6 +11,7 @@ import {
 } from '../../api/buttonStyles';
 import { Toggle } from './Toggle';
 import { useNotify } from '../../platform/hooks/useNotify';
+import { useNativeDialog } from '../../platform/hooks/useNativeDialog';
 
 type StyleValue = 'primary' | 'success' | 'danger' | 'default';
 
@@ -42,6 +43,7 @@ export function ButtonsTab() {
   const { t } = useTranslation();
   const queryClient = useQueryClient();
   const notify = useNotify();
+  const { confirm: confirmDialog } = useNativeDialog();
 
   const { data: serverStyles } = useQuery({
     queryKey: ['button-styles'],
@@ -341,8 +343,8 @@ export function ButtonsTab() {
       {/* Reset */}
       <div className="flex justify-end">
         <button
-          onClick={() => {
-            if (window.confirm(t('admin.buttons.resetConfirm'))) {
+          onClick={async () => {
+            if (await confirmDialog(t('admin.buttons.resetConfirm'))) {
               resetMutation.mutate();
             }
           }}

src/components/admin/MenuEditorTab.tsx

@@ -29,6 +29,7 @@ import {
 } from '../../api/menuLayout';
 import { Toggle } from './Toggle';
 import { useNotify } from '../../platform/hooks/useNotify';
+import { useNativeDialog } from '../../platform/hooks/useNativeDialog';
 
 const GripIcon = () => (
   <svg className="h-5 w-5" fill="none" viewBox="0 0 24 24" stroke="currentColor" strokeWidth={2}>
@@ -532,6 +533,7 @@ export function MenuEditorTab() {
   const { t } = useTranslation();
   const queryClient = useQueryClient();
   const notify = useNotify();
+  const { confirm: confirmDialog } = useNativeDialog();
 
   // Fetch config
   const {
@@ -868,8 +870,8 @@ export function MenuEditorTab() {
       {/* Reset */}
       <div className="flex justify-end">
         <button
-          onClick={() => {
-            if (window.confirm(t('admin.menuEditor.resetConfirm'))) {
+          onClick={async () => {
+            if (await confirmDialog(t('admin.menuEditor.resetConfirm'))) {
               resetMutation.mutate();
             }
           }}

src/components/admin/SettingInput.tsx

@@ -187,7 +187,7 @@ export function SettingInput({ setting, onUpdate, disabled }: SettingInputProps)
       className="group flex min-w-[100px] max-w-[200px] items-center gap-2 truncate rounded-lg border border-dark-600 bg-dark-700 px-3 py-2.5 text-left font-mono text-sm text-dark-200 transition-colors hover:border-dark-500 hover:bg-dark-600 disabled:opacity-50"
     >
       <span className="flex-1 truncate">{currentValue || '-'}</span>
-      <span className="text-dark-500 opacity-0 transition-colors group-hover:text-accent-400 group-hover:opacity-100">
+      <span className="text-dark-500 opacity-0 transition-colors group-focus-within:text-accent-400 group-focus-within:opacity-100 group-hover:text-accent-400 group-hover:opacity-100 [@media(hover:none)]:opacity-100">
         <EditIcon />
       </span>
     </button>

src/components/admin/SettingsTableRow.tsx

@@ -142,7 +142,7 @@ export function SettingsTableRow({
             <button
               onClick={onReset}
               disabled={isResetting}
-              className="flex-shrink-0 rounded-lg p-1.5 text-dark-500 opacity-0 transition-all hover:bg-dark-700 hover:text-dark-200 disabled:opacity-50 group-hover:opacity-100 max-lg:opacity-100"
+              className="flex-shrink-0 rounded-lg p-1.5 text-dark-500 opacity-0 transition-all hover:bg-dark-700 hover:text-dark-200 disabled:opacity-50 group-focus-within:opacity-100 group-hover:opacity-100 max-lg:opacity-100 [@media(hover:none)]:opacity-100"
               title={t('admin.settings.reset')}
               aria-label={t('admin.settings.reset')}
             >
@@ -157,7 +157,7 @@ export function SettingsTableRow({
               'flex-shrink-0 rounded-lg p-1.5 transition-all',
               isFavorite
                 ? 'text-warning-400 hover:bg-warning-500/15'
-                : 'text-dark-500 opacity-0 hover:bg-dark-700/50 hover:text-warning-400 group-hover:opacity-100 max-lg:opacity-100',
+                : 'text-dark-500 opacity-0 hover:bg-dark-700/50 hover:text-warning-400 group-focus-within:opacity-100 group-hover:opacity-100 max-lg:opacity-100 [@media(hover:none)]:opacity-100',
             )}
             title={
               isFavorite