fix(k8s): Correct API call signatures for k8s client v1.4

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Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/src/routes/k8s.ts

@@ -118,11 +118,7 @@ router.post('/workers/scale', async (req: Request, res: Response) => {
     await client.patchNamespacedDeploymentScale({
       name: WORKER_DEPLOYMENT,
       namespace: NAMESPACE,
-      body: {
-        spec: { replicas },
-      },
-    }, undefined, undefined, undefined, undefined, undefined, {
-      headers: { 'Content-Type': 'application/strategic-merge-patch+json' },
+      body: { spec: { replicas } },
     });
 
     console.log(`[K8s] Scaled ${WORKER_DEPLOYMENT} to ${replicas} replicas`);