Run a long task in the background of an E2B sandbox and reconnect later to collect the result

Documented steps

1. Start in background: Python `handle = sandbox.commands.run('myjob \"$JOB\" > /home/user/out.log 2>&1', background=True, timeout=0, envs={'JOB': job})`; JS `await sandbox.commands.run(cmd, { background: true, timeoutMs: 0, envs: {...} })`.
2. Persist `sandbox.sandbox_id` and `handle.pid` (e.g. in a DB or API response) - they are all a later process needs.
3. From a different process later: `sandbox = Sandbox.connect(sandbox_id)` then `handle = sandbox.commands.connect(pid)` (Python) / `await sandbox.commands.connect(pid)` (JS).
4. `handle.wait()` blocks until the command finishes, then read the file: `sandbox.files.read('/home/user/out.log')`.
5. If you do not know the pid, list running processes with `sandbox.commands.list()`.