- Combat lock: when two players actually hit each other, both are put 'in combat' for a
few seconds (config: combat.tag-seconds, default 10) and cannot turn their PvP OFF
during that time - so nobody escapes a fight by quickly disabling PvP. Turning PvP ON
is always allowed. Switch the whole feature off with combat.enabled: false.

- PlaceholderAPI support (optional): %pvpmode_status%, %pvpmode_status_plain%,
%pvpmode_enabled%, %pvpmode_combat%, %pvpmode_combat_seconds%. Runs fine without it.

- Update notice: on start the plugin checks SpigotMC for a newer version and tells
operators (permission pvpmode.update) on join. Notify-only; never downloads anything.
Toggle with update-check.enabled.

- Anonymous usage metrics via bStats (server owners can opt out in plugins/bStats).