[Feature Request] cycle triggers

[Vladimir-csp]

I understand that there are future IPC plans, but these suggestions would allow for some fire-and-forget setups:

wallpaper {
    monitor = *
    path = ~/Wallpapers/
    triggers = SIGHUP, timeout 3600, file_change
}

SIGHUP|SIGUSR1|SIGUSR2 - upon receiving a signal (maybe even have SIGHUP by default and add ExecReload=kill -HUP $MAINPID to systemd service).
timeout s - like timeout = s, just unified in triggers.
file_change [ms] - watch path for changes (new files added/removed, existing files written), cycle to new/written file(s) / away from removed. Optional milliseconds arg to wait on inactivity before doing anything (like if multiple files were copied into dir, do not trigger until everything is settled for some time).

[zhanglin2603]

Hey, I went over #340 and can take this on.

• My read: this is primarily a core implementation task tied to "[Feature Request] cycle triggers".
• I will focus on these issue-specific points first: feature, cycle, triggers.
• First I will reproduce and confirm expected behavior for the core implementation path.
• Then I will implement the fix with targeted tests and keep scope tight (good confidence).
• I will share a working PR update fast (24h for first patch, 48h for final polish) with verification notes.
  If this approach works for you, I can start now.

[zhanglin2603]

Quick follow-up on #340: I am still available to work on this issue.
If helpful, I can open a scoped first patch within 24 hours and then iterate based on your feedback.
No rush either way; if someone is already assigned, just let me know and I will step back.