chore: import upstream snapshot with attribution

apps/sim/lib/monitoring/memory-telemetry.ts

@@ -0,0 +1,39 @@
+/**
+ * Periodic memory telemetry for monitoring heap growth in production.
+ * Logs process.memoryUsage() and V8 heap stats every 60s.
+ */
+
+import v8 from 'node:v8'
+import { createLogger } from '@sim/logger'
+
+const logger = createLogger('MemoryTelemetry', { logLevel: 'INFO' })
+
+const MB = 1024 * 1024
+
+let started = false
+
+export function startMemoryTelemetry(intervalMs = 60_000) {
+  if (started) return
+  started = true
+
+  const timer = setInterval(() => {
+    const mem = process.memoryUsage()
+    const heap = v8.getHeapStatistics()
+
+    logger.info('Memory snapshot', {
+      heapUsedMB: Math.round(mem.heapUsed / MB),
+      heapTotalMB: Math.round(mem.heapTotal / MB),
+      rssMB: Math.round(mem.rss / MB),
+      externalMB: Math.round(mem.external / MB),
+      arrayBuffersMB: Math.round(mem.arrayBuffers / MB),
+      heapSizeLimitMB: Math.round(heap.heap_size_limit / MB),
+      nativeContexts: heap.number_of_native_contexts,
+      activeResources:
+        typeof process.getActiveResourcesInfo === 'function'
+          ? process.getActiveResourcesInfo().length
+          : -1,
+      uptimeMin: Math.round(process.uptime() / 60),
+    })
+  }, intervalMs)
+  timer.unref()
+}