feat(idle): suspend after 10 min of lid-open idle

The panel powered off at 330s but nothing ever suspended, so a lid-open idle
laptop kept drawing 6-7W indefinitely; only lid *close* suspended (logind's
default HandleLidSwitch). logind IdleAction stays Ignore on purpose -- it
cannot run swaymsg/hyprlock hooks, hypridle's before_sleep_cmd can.
Plain suspend, not suspend-then-hibernate: swap is zram-only.

.config/hypr/hypridle.conf

@@ -46,3 +46,18 @@ listener {
     on-timeout = swaymsg "output * power off"
     on-resume = swaymsg "output * power on" && brightnessctl -r
 }
+# 10min -> s2idle. This listener used to be missing entirely: the panel powered
+# off at 330s but the machine never suspended, so a lid-open idle laptop kept
+# draining ~6-7W (10h battery) forever. Closing the lid did suspend, because
+# logind's default HandleLidSwitch=suspend -- but only the lid path.
+# logind's own IdleAction stays Ignore on purpose (it cannot run swaymsg/hyprlock
+# pre-sleep hooks; hypridle's before_sleep_cmd can).
+# 600s = long enough that a compile/syncthing burst usually finishes; a suspend
+# mid-task is recoverable, and before_sleep_cmd locks on resume.
+# Verified: polkit org.freedesktop.login1.suspend allow_active=yes, so this
+# needs no auth prompt from an active local session. Plain suspend (not
+# suspend-then-hibernate) because swap is zram-only -> hibernate impossible.
+listener {
+    timeout = 600                                # 10min -> suspend
+    on-timeout = systemctl suspend
+}