fix(dashboard): улучшить логику загрузки данных на странице панели управления

app/(main)/dashboard/page.tsx

@@ -691,7 +691,8 @@ export default function DashboardPage() {
       }
     }
 
-    const loadingBlock = probesLoading && liveProbes === null
+    const liveDataPending = liveServersResolved === null || liveProbes === null
+    const loadingBlock = liveDataPending || (probesLoading && liveProbes === null)
     const srvList = liveServersResolved ?? []
     const totalSrv = srvList.length
     const onlineSrv = srvList.filter((s) => s.status === "online").length

lib/data-source.tsx

@@ -59,13 +59,9 @@ function normalizeBackendUrl(url: string): string {
 }
 
 export function DataSourceProvider({ children }: { children: React.ReactNode }) {
-  const [mode, setModeState] = useState<DataSourceMode>(() =>
-    typeof window === "undefined" ? defaultDataSourceMode() : readStoredMode(),
-  )
-  const [backendUrl, setBackendUrlState] = useState(() =>
-    typeof window === "undefined" ? LOCAL_DEFAULT_BACKEND_URL : readStoredBackendUrl(),
-  )
-  const [prefsHydrated, setPrefsHydrated] = useState(() => typeof window !== "undefined")
+  const [mode, setModeState] = useState<DataSourceMode>(defaultDataSourceMode)
+  const [backendUrl, setBackendUrlState] = useState(LOCAL_DEFAULT_BACKEND_URL)
+  const [prefsHydrated, setPrefsHydrated] = useState(false)
   const [backendStatus, setBackendStatus] = useState<boolean | undefined>(undefined)
   const backendUrlLocked = isBackendUrlLocked()
   const mockModeAvailable = isMockDataSourceAvailable()