feat: add multi-channel subscription blocking UI and admin management

- Channel subscription blocking screen with per-channel status display
- Safe URL handling with protocol validation (no open redirect)
- Race-condition-safe subscription check with useRef guard
- Admin channel management page with create, toggle, delete
- Error handlers on all admin mutations with haptic feedback
- Proper type guard for channel subscription error detection
- Accessibility: aria-labels on icon-only buttons
- Localization: en, ru, zh, fa translations

src/pages/AdminChannelSubscriptions.tsx

@@ -0,0 +1,408 @@
+import { useState } from 'react';
+import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
+import { useTranslation } from 'react-i18next';
+import { useHaptic, useNotify } from '../platform';
+import {
+  adminChannelsApi,
+  type RequiredChannel,
+  type CreateChannelRequest,
+} from '../api/adminChannels';
+import { AdminBackButton } from '../components/admin';
+
+// Icons
+const ChannelIcon = () => (
+  <svg className="h-6 w-6" fill="none" viewBox="0 0 24 24" stroke="currentColor" strokeWidth={1.5}>
+    <path
+      strokeLinecap="round"
+      strokeLinejoin="round"
+      d="M10.34 15.84c-.688-.06-1.386-.09-2.09-.09H7.5a4.5 4.5 0 110-9h.75c.704 0 1.402-.03 2.09-.09m0 9.18c.253.962.584 1.892.985 2.783.247.55.06 1.21-.463 1.511l-.657.38c-.551.318-1.26.117-1.527-.461a20.845 20.845 0 01-1.44-4.282m3.102.069a18.03 18.03 0 01-.59-4.59c0-1.586.205-3.124.59-4.59m0 9.18a23.848 23.848 0 018.835 2.535M10.34 6.66a23.847 23.847 0 008.835-2.535m0 0A23.74 23.74 0 0018.795 3m.38 1.125a23.91 23.91 0 011.014 5.395m-1.014 8.855c-.118.38-.245.754-.38 1.125m.38-1.125a23.91 23.91 0 001.014-5.395m0-3.46c.495.413.811 1.035.811 1.73 0 .695-.316 1.317-.811 1.73m0-3.46a24.347 24.347 0 010 3.46"
+    />
+  </svg>
+);
+
+const PlusIcon = () => (
+  <svg className="h-5 w-5" fill="none" viewBox="0 0 24 24" stroke="currentColor" strokeWidth={2}>
+    <path strokeLinecap="round" strokeLinejoin="round" d="M12 4.5v15m7.5-7.5h-15" />
+  </svg>
+);
+
+const RefreshIcon = () => (
+  <svg className="h-4 w-4" fill="none" viewBox="0 0 24 24" stroke="currentColor" strokeWidth={2}>
+    <path
+      strokeLinecap="round"
+      strokeLinejoin="round"
+      d="M16.023 9.348h4.992v-.001M2.985 19.644v-4.992m0 0h4.992m-4.993 0l3.181 3.183a8.25 8.25 0 0013.803-3.7M4.031 9.865a8.25 8.25 0 0113.803-3.7l3.181 3.182m0-4.991v4.99"
+    />
+  </svg>
+);
+
+const TrashIcon = () => (
+  <svg className="h-4 w-4" fill="none" viewBox="0 0 24 24" stroke="currentColor" strokeWidth={2}>
+    <path
+      strokeLinecap="round"
+      strokeLinejoin="round"
+      d="M14.74 9l-.346 9m-4.788 0L9.26 9m9.968-3.21c.342.052.682.107 1.022.166m-1.022-.165L18.16 19.673a2.25 2.25 0 01-2.244 2.077H8.084a2.25 2.25 0 01-2.244-2.077L4.772 5.79m14.456 0a48.108 48.108 0 00-3.478-.397m-12 .562c.34-.059.68-.114 1.022-.165m0 0a48.11 48.11 0 013.478-.397m7.5 0v-.916c0-1.18-.91-2.164-2.09-2.201a51.964 51.964 0 00-3.32 0c-1.18.037-2.09 1.022-2.09 2.201v.916m7.5 0a48.667 48.667 0 00-7.5 0"
+    />
+  </svg>
+);
+
+const CheckIcon = () => (
+  <svg className="h-4 w-4" fill="none" viewBox="0 0 24 24" stroke="currentColor" strokeWidth={2}>
+    <path strokeLinecap="round" strokeLinejoin="round" d="M4.5 12.75l6 6 9-13.5" />
+  </svg>
+);
+
+const XIcon = () => (
+  <svg className="h-4 w-4" fill="none" viewBox="0 0 24 24" stroke="currentColor" strokeWidth={2}>
+    <path strokeLinecap="round" strokeLinejoin="round" d="M6 18L18 6M6 6l12 12" />
+  </svg>
+);
+
+const LinkIcon = () => (
+  <svg className="h-4 w-4" fill="none" viewBox="0 0 24 24" stroke="currentColor" strokeWidth={2}>
+    <path
+      strokeLinecap="round"
+      strokeLinejoin="round"
+      d="M13.19 8.688a4.5 4.5 0 011.242 7.244l-4.5 4.5a4.5 4.5 0 01-6.364-6.364l1.757-1.757m9.86-2.239a4.5 4.5 0 00-1.242-7.244l-4.5-4.5a4.5 4.5 0 00-6.364 6.364L4.5 8.688"
+    />
+  </svg>
+);
+
+// Channel card component
+function ChannelCard({
+  channel,
+  onToggle,
+  onDelete,
+}: {
+  channel: RequiredChannel;
+  onToggle: (id: number) => void;
+  onDelete: (id: number) => void;
+}) {
+  const { t } = useTranslation();
+
+  const displayName = channel.title || channel.channel_id;
+  const hasLink = !!channel.channel_link;
+
+  return (
+    <div
+      className={`rounded-xl border p-4 transition-all ${
+        channel.is_active
+          ? 'border-success-500/50 bg-success-500/5'
+          : 'border-dark-700 bg-dark-800/50'
+      }`}
+    >
+      <div className="flex items-start justify-between gap-3">
+        <div className="min-w-0 flex-1">
+          {/* Status + sort order */}
+          <div className="mb-2 flex flex-wrap items-center gap-2">
+            <span
+              className={`rounded-full px-2 py-1 text-xs font-medium ${
+                channel.is_active
+                  ? 'bg-success-500/20 text-success-400'
+                  : 'bg-dark-500/20 text-dark-400'
+              }`}
+            >
+              {channel.is_active
+                ? t('admin.channelSubscriptions.enabled')
+                : t('admin.channelSubscriptions.disabled')}
+            </span>
+            <span className="text-xs text-dark-400">#{channel.id}</span>
+            <span className="text-xs text-dark-500">
+              {t('admin.channelSubscriptions.sortOrder')}: {channel.sort_order}
+            </span>
+          </div>
+
+          {/* Title / channel_id */}
+          <p className="text-sm font-medium text-dark-100">{displayName}</p>
+
+          {/* Channel ID (if title exists, show ID separately) */}
+          {channel.title && <p className="mt-0.5 text-xs text-dark-400">{channel.channel_id}</p>}
+
+          {/* Link */}
+          {hasLink && (
+            <div className="mt-1.5 flex items-center gap-1 text-xs text-accent-400">
+              <LinkIcon />
+              <a
+                href={channel.channel_link!}
+                target="_blank"
+                rel="noopener noreferrer"
+                className="truncate hover:underline"
+              >
+                {channel.channel_link}
+              </a>
+            </div>
+          )}
+        </div>
+      </div>
+
+      {/* Action buttons */}
+      <div className="mt-3 flex flex-wrap gap-2 border-t border-dark-700/50 pt-3">
+        {channel.is_active ? (
+          <button
+            onClick={() => onToggle(channel.id)}
+            className="flex items-center gap-1.5 rounded-lg bg-warning-500/20 px-3 py-1.5 text-xs text-warning-400 transition-colors hover:bg-warning-500/30"
+          >
+            <XIcon />
+            {t('admin.channelSubscriptions.disable')}
+          </button>
+        ) : (
+          <button
+            onClick={() => onToggle(channel.id)}
+            className="flex items-center gap-1.5 rounded-lg bg-success-500/20 px-3 py-1.5 text-xs text-success-400 transition-colors hover:bg-success-500/30"
+          >
+            <CheckIcon />
+            {t('admin.channelSubscriptions.enable')}
+          </button>
+        )}
+
+        <button
+          onClick={() => onDelete(channel.id)}
+          className="flex items-center gap-1.5 rounded-lg bg-error-500/20 px-3 py-1.5 text-xs text-error-400 transition-colors hover:bg-error-500/30"
+        >
+          <TrashIcon />
+          {t('admin.channelSubscriptions.delete')}
+        </button>
+      </div>
+    </div>
+  );
+}
+
+// Add channel form component
+function AddChannelForm({
+  onSubmit,
+  onCancel,
+  isLoading,
+}: {
+  onSubmit: (data: CreateChannelRequest) => void;
+  onCancel: () => void;
+  isLoading: boolean;
+}) {
+  const { t } = useTranslation();
+  const [channelId, setChannelId] = useState('');
+  const [channelLink, setChannelLink] = useState('');
+  const [title, setTitle] = useState('');
+
+  const handleSubmit = () => {
+    if (!channelId.trim()) return;
+    onSubmit({
+      channel_id: channelId.trim(),
+      channel_link: channelLink.trim() || undefined,
+      title: title.trim() || undefined,
+    });
+  };
+
+  return (
+    <div className="rounded-xl border border-accent-500/30 bg-dark-800/50 p-4">
+      <div className="space-y-3">
+        {/* Channel ID (required) */}
+        <div>
+          <label className="mb-1 block text-xs font-medium text-dark-300">
+            {t('admin.channelSubscriptions.form.channelId')} *
+          </label>
+          <input
+            type="text"
+            value={channelId}
+            onChange={(e) => setChannelId(e.target.value)}
+            placeholder={t('admin.channelSubscriptions.form.channelIdHint')}
+            className="w-full rounded-lg border border-dark-600 bg-dark-700 px-3 py-2 text-sm text-dark-100 placeholder-dark-500 outline-none transition-colors focus:border-accent-500"
+            autoFocus
+          />
+        </div>
+
+        {/* Title (optional) */}
+        <div>
+          <label className="mb-1 block text-xs font-medium text-dark-300">
+            {t('admin.channelSubscriptions.form.title')}
+          </label>
+          <input
+            type="text"
+            value={title}
+            onChange={(e) => setTitle(e.target.value)}
+            placeholder={t('admin.channelSubscriptions.form.title')}
+            className="w-full rounded-lg border border-dark-600 bg-dark-700 px-3 py-2 text-sm text-dark-100 placeholder-dark-500 outline-none transition-colors focus:border-accent-500"
+          />
+        </div>
+
+        {/* Channel Link (optional) */}
+        <div>
+          <label className="mb-1 block text-xs font-medium text-dark-300">
+            {t('admin.channelSubscriptions.form.channelLink')}
+          </label>
+          <input
+            type="text"
+            value={channelLink}
+            onChange={(e) => setChannelLink(e.target.value)}
+            placeholder={t('admin.channelSubscriptions.form.channelLinkHint')}
+            className="w-full rounded-lg border border-dark-600 bg-dark-700 px-3 py-2 text-sm text-dark-100 placeholder-dark-500 outline-none transition-colors focus:border-accent-500"
+          />
+        </div>
+
+        {/* Buttons */}
+        <div className="flex gap-2 pt-1">
+          <button
+            onClick={handleSubmit}
+            disabled={!channelId.trim() || isLoading}
+            className="flex items-center gap-2 rounded-lg bg-accent-500 px-4 py-2 text-sm text-white transition-colors hover:bg-accent-600 disabled:cursor-not-allowed disabled:opacity-50"
+          >
+            <CheckIcon />
+            {t('admin.channelSubscriptions.form.submit')}
+          </button>
+          <button
+            onClick={onCancel}
+            disabled={isLoading}
+            className="flex items-center gap-2 rounded-lg bg-dark-700 px-4 py-2 text-sm text-dark-300 transition-colors hover:bg-dark-600 disabled:cursor-not-allowed disabled:opacity-50"
+          >
+            <XIcon />
+            {t('admin.channelSubscriptions.form.cancel')}
+          </button>
+        </div>
+      </div>
+    </div>
+  );
+}
+
+// Main component
+export default function AdminChannelSubscriptions() {
+  const { t } = useTranslation();
+  const queryClient = useQueryClient();
+  const haptic = useHaptic();
+  const notify = useNotify();
+  const [showAddForm, setShowAddForm] = useState(false);
+
+  // Fetch channels
+  const { data, isLoading, refetch } = useQuery({
+    queryKey: ['admin-channels'],
+    queryFn: adminChannelsApi.list,
+  });
+
+  const toggleMutation = useMutation({
+    mutationFn: (id: number) => adminChannelsApi.toggle(id),
+    onSuccess: () => {
+      queryClient.invalidateQueries({ queryKey: ['admin-channels'] });
+      haptic.impact('light');
+    },
+    onError: () => {
+      haptic.notification('error');
+      notify.error(t('common.error'));
+    },
+  });
+
+  const deleteMutation = useMutation({
+    mutationFn: (id: number) => adminChannelsApi.delete(id),
+    onSuccess: () => {
+      queryClient.invalidateQueries({ queryKey: ['admin-channels'] });
+      haptic.impact('medium');
+    },
+    onError: () => {
+      haptic.notification('error');
+      notify.error(t('common.error'));
+    },
+  });
+
+  const createMutation = useMutation({
+    mutationFn: (req: CreateChannelRequest) => adminChannelsApi.create(req),
+    onSuccess: () => {
+      queryClient.invalidateQueries({ queryKey: ['admin-channels'] });
+      setShowAddForm(false);
+      haptic.impact('light');
+    },
+    onError: () => {
+      haptic.notification('error');
+      notify.error(t('common.error'));
+    },
+  });
+
+  const handleToggle = (id: number) => {
+    toggleMutation.mutate(id);
+  };
+
+  const handleDelete = (id: number) => {
+    if (window.confirm(t('admin.channelSubscriptions.deleteConfirm'))) {
+      deleteMutation.mutate(id);
+    }
+  };
+
+  const handleCreate = (data: CreateChannelRequest) => {
+    createMutation.mutate(data);
+  };
+
+  const channels = data?.items ?? [];
+
+  return (
+    <div className="space-y-6">
+      {/* Header */}
+      <div className="flex items-center justify-between">
+        <div className="flex items-center gap-3">
+          <AdminBackButton />
+          <div className="flex items-center gap-3">
+            <div className="rounded-lg bg-accent-500/20 p-2 text-accent-400">
+              <ChannelIcon />
+            </div>
+            <div>
+              <h1 className="text-xl font-bold text-dark-100">
+                {t('admin.channelSubscriptions.title')}
+              </h1>
+              <p className="text-sm text-dark-400">{t('admin.channelSubscriptions.subtitle')}</p>
+            </div>
+          </div>
+        </div>
+        <div className="flex gap-2">
+          <button
+            onClick={() => refetch()}
+            aria-label={t('common.refresh')}
+            className="rounded-lg bg-dark-800 p-2 text-dark-400 transition-colors hover:text-dark-100"
+          >
+            <RefreshIcon />
+          </button>
+          {!showAddForm && (
+            <button
+              onClick={() => setShowAddForm(true)}
+              aria-label={t('admin.channelSubscriptions.addChannel')}
+              className="flex items-center gap-2 rounded-lg bg-accent-500 px-4 py-2 text-white transition-colors hover:bg-accent-600"
+            >
+              <PlusIcon />
+              <span className="hidden sm:inline">{t('admin.channelSubscriptions.addChannel')}</span>
+            </button>
+          )}
+        </div>
+      </div>
+
+      {/* Add form */}
+      {showAddForm && (
+        <AddChannelForm
+          onSubmit={handleCreate}
+          onCancel={() => setShowAddForm(false)}
+          isLoading={createMutation.isPending}
+        />
+      )}
+
+      {/* Channel list */}
+      {isLoading ? (
+        <div className="rounded-xl border border-dark-700 bg-dark-800/50 p-8 text-center text-dark-400">
+          <div className="mx-auto mb-2 w-fit animate-spin">
+            <RefreshIcon />
+          </div>
+          <p>{t('common.loading')}</p>
+        </div>
+      ) : channels.length === 0 ? (
+        <div className="rounded-xl border border-dark-700 bg-dark-800/50 p-8 text-center text-dark-400">
+          <div className="mx-auto mb-2 w-fit">
+            <ChannelIcon />
+          </div>
+          <p>{t('admin.channelSubscriptions.empty')}</p>
+        </div>
+      ) : (
+        <div className="space-y-3">
+          {channels.map((channel: RequiredChannel) => (
+            <ChannelCard
+              key={channel.id}
+              channel={channel}
+              onToggle={handleToggle}
+              onDelete={handleDelete}
+            />
+          ))}
+        </div>
+      )}
+    </div>
+  );
+}

src/pages/AdminPanel.tsx

@@ -482,6 +482,12 @@ export default function AdminPanel() {
       iconBg: 'bg-violet-500/20',
       iconColor: 'text-violet-400',
       items: [
+        {
+          to: '/admin/channel-subscriptions',
+          icon: <MegaphoneIcon />,
+          title: t('admin.nav.channelSubscriptions'),
+          description: t('admin.panel.channelSubscriptionsDesc'),
+        },
         {
           to: '/admin/settings',
           icon: <CogIcon />,