aw-qt blocks system suspend (task refuses to freeze during suspend)

I am on the latest ActivityWatch version.
I have searched the issues of this repo and believe that this is not a duplicate.

OS name and version: Ubuntu 22.04.5 LTS (Jammy Jellyfish)
ActivityWatch version: v0.13.2
Install method: AppImage (activitywatch-linux-x86_64.AppImage)

**Describe the bug**
System suspend fails because `aw-qt` refuses to freeze. The kernel reports that a userspace task won’t freeze and the suspend aborts, returning immediately.

**To Reproduce**
1. Run ActivityWatch normally (aw-qt, aw-watcher-window active).
2. Trigger system suspend (e.g., close lid or leave idle).
3. Suspend fails with a “task refusing to freeze” message.

**Expected behavior**
ActivityWatch should not block suspend. If a watcher hangs, it should not prevent the system from suspending.

**Documentation**

`journalctl` around the failed suspend:

Feb 08 13:25:56 user2-123 systemd-sleep[557864]: Entering sleep state 'suspend'...
Feb 08 13:25:56 user2-123 kernel: PM: suspend entry (deep)
Feb 08 13:26:00 user2-123 kernel: Wakeup pending. Abort CPU freeze
Feb 08 13:26:00 user2-123 kernel: ACPI: PM: Waking up from system sleep state S3
Feb 08 13:26:00 user2-123 kernel: PM: suspend exit
Feb 08 13:26:00 user2-123 kernel: PM: suspend entry (s2idle)
Feb 08 13:26:20 user2-123 kernel: Freezing user space processes failed after 20.006 seconds (1 tasks refusing to freeze, wq_busy=0):
Feb 08 13:26:20 user2-123 kernel: task:aw-qt state:D stack:0 pid:4214 tgid:4214 ppid:4000 flags:0x00000006
Feb 08 13:26:20 user2-123 kernel: PM: suspend exit
Feb 08 13:26:20 user2-123 systemd-sleep[557864]: Failed to put system to sleep. System resumed again: Device or resource busy

aw-qt log (same boot after resume/restart):

2026-02-08 13:47:59 [INFO ]: Started aw-qt... (aw_qt.main:53)
2026-02-08 13:47:59 [WARNING]: Found matching file but was not executable: /tmp/.mount_activiNgXZi1/aw-qt.desktop (aw_qt.manager:64)
2026-02-08 13:47:59 [INFO ]: Found 8 bundled modules (aw_qt.manager:85)
2026-02-08 13:47:59 [INFO ]: Starting module aw-server (aw_qt.manager:148)
2026-02-08 13:47:59 [INFO ]: Starting module aw-watcher-afk (aw_qt.manager:148)
2026-02-08 13:47:59 [INFO ]: Starting module aw-watcher-window (aw_qt.manager:148)
2026-02-08 13:47:59 [INFO ]: Initialized aw-qt and trayicon successfully (aw_qt.trayicon:264)

aw-watcher-window log:

2026-02-08 13:48:00 [INFO ]: aw-watcher-window started (aw_watcher_window.main:70)
2026-02-08 13:48:01 [INFO ]: Connection to aw-server established by aw-watcher-window (aw_client.client:447)

**Additional context**
KDE Plasma 5.24.7 on X11, AMD Renoir GPU. External monitor was connected when the suspend happened.