fix(beszel): use bandwidth field (b) for public interface traffic

In Beszel, ns/nr are all-interface traffic (loopback, docker bridges)
while b is public interface bandwidth. Use b with ns/nr fallback for
both system stats and container network charts to match what the
grid/table display via netBytes.

packages/widgets/src/beszel-system-stats/component.tsx

@@ -76,9 +76,9 @@ export default function BeszelSystemStatsWidget({
     [t],
   );
   const networkMap = useCallback(
-    (s: { ns: number; nr: number }) => ({
-      [t("chart.network.sent")]: s.ns,
-      [t("chart.network.recv")]: s.nr,
+    (s: { ns: number; nr: number; b?: [number, number] }) => ({
+      [t("chart.network.sent")]: s.b?.[0] ?? s.ns,
+      [t("chart.network.recv")]: s.b?.[1] ?? s.nr,
     }),
     [t],
   );

packages/widgets/src/beszel/_shared/chart.tsx

@@ -85,7 +85,7 @@ type ContainerExtractor = (container: BeszelContainerStatsRecord["stats"][number
 const defaultContainerExtractors: Record<string, ContainerExtractor> = {
   cpu: (c) => c?.c ?? 0,
   memory: (c) => c?.m ?? 0,
-  network: (c) => (c?.ns ?? 0) + (c?.nr ?? 0),
+  network: (c) => c?.b ? c.b[0] + c.b[1] : (c?.ns ?? 0) + (c?.nr ?? 0),
 };
 
 export const useDockerChartData = (