feat: port critical battery alert from DankBatteryAlerts plugin (#2664)

* feat: port critical battery alert from DankBatteryAlerts plugin

* ui: shorten notification type labels

* refactor: remove duplicate battery charge limit from Power & Sleep

quickshell/Common/SettingsData.qml

@@ -599,6 +599,8 @@ Singleton {
     property int batteryPostLockMonitorTimeout: 0
     property int batteryChargeLimit: 100
     property bool batteryNotifyChargeLimit: false
+    property int batteryCriticalThreshold: 10
+    property bool batteryNotifyCritical: true
     property int batteryLowThreshold: 20
     property bool batteryNotifyLow: false
     property int batteryNotificationType: 0

quickshell/Common/settings/SettingsSpec.js

@@ -306,6 +306,8 @@ var SPEC = {
     batteryPostLockMonitorTimeout: { def: 0 },
     batteryChargeLimit: { def: 100 },
     batteryNotifyChargeLimit: { def: false },
+    batteryCriticalThreshold: { def: 10 },
+    batteryNotifyCritical: { def: true },
     batteryLowThreshold: { def: 20 },
     batteryNotifyLow: { def: false },
     batteryNotificationType: { def: 0 },