chore: import upstream snapshot with attribution

scripts/run-with-managed-node.js

@@ -0,0 +1,91 @@
+import os from 'node:os'
+import path from 'node:path'
+import { spawn } from 'node:child_process'
+import fs from 'node:fs'
+
+const DEFAULT_LEON_HOME_DIRNAME = '.leon'
+// Must match server/src/core/server-lifecycle.ts.
+const LEON_RESTART_EXIT_CODE = 77
+
+/**
+ * This launcher must stay plain-Node compatible because it is invoked before
+ * tsx/path aliases are available.
+ */
+function resolveLeonHomePath() {
+  const configuredLeonHome = String(process.env['LEON_HOME'] || '').trim()
+
+  return configuredLeonHome
+    ? path.resolve(configuredLeonHome)
+    : path.join(os.homedir(), DEFAULT_LEON_HOME_DIRNAME)
+}
+
+const leonHomePath = resolveLeonHomePath()
+const managedNodePath = process.platform === 'win32'
+  ? path.join(leonHomePath, 'bin', 'node', 'node.exe')
+  : path.join(leonHomePath, 'bin', 'node', 'bin', 'node')
+const args = process.argv.slice(2)
+
+if (!fs.existsSync(managedNodePath)) {
+  console.error(
+    `Managed Node.js binary not found at "${managedNodePath}". Run "pnpm run postinstall" first.`
+  )
+  process.exit(1)
+}
+
+if (args.length === 0) {
+  console.error('No script was provided to the managed Node.js launcher.')
+  process.exit(1)
+}
+
+let child = null
+let shouldRestart = true
+
+function startManagedProcess() {
+  child = spawn(managedNodePath, args, {
+    cwd: process.cwd(),
+    stdio: 'inherit',
+    windowsHide: true
+  })
+
+  child.on('error', (error) => {
+    console.error(error)
+    process.exit(1)
+  })
+
+  child.on('exit', (code, signal) => {
+    child = null
+
+    if (signal) {
+      process.kill(process.pid, signal)
+      return
+    }
+
+    if (shouldRestart && code === LEON_RESTART_EXIT_CODE) {
+      startManagedProcess()
+      return
+    }
+
+    process.exit(code ?? 0)
+  })
+}
+
+function stopManagedProcess(signal) {
+  shouldRestart = false
+
+  if (child?.pid) {
+    child.kill(signal)
+    return
+  }
+
+  process.exit(0)
+}
+
+process.on('SIGINT', () => {
+  stopManagedProcess('SIGINT')
+})
+
+process.on('SIGTERM', () => {
+  stopManagedProcess('SIGTERM')
+})
+
+startManagedProcess()