refactor: simplify request handlers and deduplicate config

- Re-enable TanStack Query retry (retry: 3 with exponential backoff),
  delete all server-side retry logic from request handlers
- Strip handler factories to bare minimum: remove isValid, retry, widgetKind
- Remove redundant refetchOnWindowFocus/refetchOnReconnect from docker-table
- Deduplicate queryCacheMaxValueBytes (pass as param, single source of truth)
- Simplify system-resources chart: use dataUpdatedAt instead of ref-based tracking
- Fix leading blank lines in 27 request handler files

apps/nextjs/src/app/[locale]/_client-providers/trpc.tsx

@@ -71,7 +71,7 @@ export function TRPCReactProvider(props: PropsWithChildren) {
             gcTime: queryCacheDefaultGcTimeMs,
             refetchOnWindowFocus: false,
             refetchOnReconnect: false,
-            retry: false,
+            retry: 3,
           },
           mutations: {
             onError(error) {

apps/nextjs/src/app/[locale]/manage/tools/docker/docker-table.tsx

@@ -156,8 +156,6 @@ export function DockerTable({ containers, timestamp }: RouterOutputs["docker"]["
   const { data } = clientApi.docker.getContainers.useQuery(undefined, {
     initialData: { containers, timestamp },
     refetchOnMount: false,
-    refetchOnWindowFocus: false,
-    refetchOnReconnect: false,
   });
   const relativeTime = useTimeAgo(data.timestamp);
   const utils = clientApi.useUtils();