perf: fix render cycle in useBranding and conditional polling

- Remove isFullscreen from useBranding useEffect deps to prevent
  re-render loop (requestFullscreen changes isFullscreen which
  re-triggers the effect); use ref guard instead
- Make AdminBroadcasts 5s polling conditional: only poll when there
  are active broadcasts (queued/in_progress/cancelling)

src/hooks/useBranding.ts

@@ -1,4 +1,4 @@
-import { useEffect } from 'react';
+import { useEffect, useRef } from 'react';
 import { useQuery } from '@tanstack/react-query';
 import { useAuthStore } from '@/store/auth';
 import { useTelegramSDK, setCachedFullscreenEnabled } from '@/hooks/useTelegramSDK';
@@ -14,8 +14,8 @@ const FALLBACK_NAME = import.meta.env.VITE_APP_NAME || 'Cabinet';
 const FALLBACK_LOGO = import.meta.env.VITE_APP_LOGO || 'V';
 
 export function useBranding() {
-  const { isAuthenticated } = useAuthStore();
-  const { isFullscreen, isTelegramWebApp, requestFullscreen, isMobile } = useTelegramSDK();
+  const isAuthenticated = useAuthStore((state) => state.isAuthenticated);
+  const { isTelegramWebApp, requestFullscreen, isMobile } = useTelegramSDK();
 
   // Branding data
   const { data: branding } = useQuery({
@@ -62,13 +62,16 @@ export function useBranding() {
     staleTime: 60000,
   });
 
+  const fullscreenRequestedRef = useRef(false);
+
   useEffect(() => {
     if (!fullscreenSetting || !isTelegramWebApp) return;
     setCachedFullscreenEnabled(fullscreenSetting.enabled);
-    if (fullscreenSetting.enabled && !isFullscreen && isMobile) {
+    if (fullscreenSetting.enabled && isMobile && !fullscreenRequestedRef.current) {
+      fullscreenRequestedRef.current = true;
       requestFullscreen();
     }
-  }, [fullscreenSetting, isTelegramWebApp, isFullscreen, requestFullscreen, isMobile]);
+  }, [fullscreenSetting, isTelegramWebApp, requestFullscreen, isMobile]);
 
   return {
     appName,

src/pages/AdminBroadcasts.tsx

@@ -137,7 +137,13 @@ export default function AdminBroadcasts() {
   const { data, isLoading, refetch } = useQuery({
     queryKey: ['admin', 'broadcasts', 'list', page],
     queryFn: () => adminBroadcastsApi.list(limit, page * limit),
-    refetchInterval: 5000, // Auto refresh every 5s
+    refetchInterval: (query) => {
+      const items = query.state.data?.items;
+      const hasActive = items?.some((b: { status: string }) =>
+        ['queued', 'in_progress', 'cancelling'].includes(b.status),
+      );
+      return hasActive ? 5000 : false;
+    },
   });
 
   const broadcasts = data?.items || [];