fix: pass base_cmd to background commander thread so commands actually run

[rezasabourinejad]

Summary

When commander() is called with run_in_background=True (the default), the background command is never executed. The worker thread is created without forwarding the constructed base_cmd:

if run_in_background:
    t = threading.Thread(target=cmd_in_back, daemon=True)  # base_cmd is not passed
    t.start()
...
def cmd_in_back(cmd):  # cmd is required
    p = subprocess.Popen(cmd, ...)
    p.wait()

So cmd_in_back() is invoked with no arguments and raises immediately, before subprocess.Popen ever runs:

TypeError: cmd_in_back() missing 1 required positional argument: 'cmd'

The thread is a daemon and the exception is only logged, so the calling task/request still appears to "succeed" while having no effect.

Impact

Every background commander() action silently does nothing, including:

• Command.apply — the panel "Apply configuration" action; configs are never regenerated and no progress/log is shown in the panel.
• Command.apply_users — added / removed / disabled users are never written to the live proxy config.
• Command.restart_services, Command.update, Command.install, Command.get_cert, etc.

This has a real security / billing impact for anyone running paid or private nodes:

• A user whose account is deleted stays connected, because apply_users never removes their UUID from the live sing-box / xray config.
• A user who is over quota or past their expiry date stays connected, because the automatic disable + apply never takes effect on the live config.

So revocation from the panel does not actually cut users off until some run_in_background=False path (e.g. a manual bash apply_configs.sh on the server) happens to regenerate the config.

Root cause

Regression introduced in 4adef40 ("fix: zombie process"), which moved the background subprocess.Popen(base_cmd, ...) into a cmd_in_back thread (to wait() on and reap the child) but did not forward base_cmd to the thread.

Fix

Pass base_cmd to the thread:

t = threading.Thread(target=cmd_in_back, args=(base_cmd,), daemon=True)

Testing

Reproduced and verified on a 12.3.x deployment. Before the fix, the background-tasks worker logged the TypeError on every panel apply and deleted / expired users remained connected to the live config. After this one-line change, the background command runs: the panel apply executes (progress/log returns) and user revocations take effect.