fix(cutover): use direct detached spawn

apps/api/src/cutover-orchestrator.ts

@@ -1,4 +1,4 @@
-import { execFile, execFileSync } from 'node:child_process';
+import { execFile, spawn } from 'node:child_process';
 import { constants } from 'node:fs';
 import {
   access,
@@ -159,22 +159,14 @@ export const nodeCutoverSystem: CutoverSystem = {
     throw new Error(`PID ${pid} did not exit after SIGTERM`);
   },
   start(argv, environment) {
-    const output = execFileSync(
-      '/usr/bin/python3',
-      [
-        '-c',
-        "import os,sys; pid=os.fork(); (os.write(1,(str(pid)+'\\n').encode()) and os._exit(0)) if pid else (os.setsid(), (lambda fd:(os.dup2(fd,0),os.dup2(fd,1),os.dup2(fd,2),os.close(fd) if fd>2 else None))(os.open(os.devnull,os.O_RDWR)), os.execve(sys.argv[1],sys.argv[1:],dict(os.environ)))",
-        ...argv,
-      ],
-      {
-        encoding: 'utf8',
-        env: environment ?? process.env,
-        stdio: ['ignore', 'pipe', 'ignore'],
-      },
-    );
-    const pid = Number(output.trim().split(/\s+/u)[0]);
-    if (!Number.isSafeInteger(pid) || pid <= 1) throw new Error('Failed to start command');
-    return pid;
+    const child = spawn(argv[0], argv.slice(1), {
+      detached: true,
+      stdio: 'ignore',
+      env: environment ?? process.env,
+    });
+    child.unref();
+    if (!child.pid) throw new Error('Failed to start command');
+    return child.pid;
   },
   delay: (milliseconds) => new Promise((resolveWait) => setTimeout(resolveWait, milliseconds)),
 };