Give player species slight passive regen (#20638)

* Implementation

* Reviews

Content.Shared/Damage/Components/PassiveDamageComponent.cs

@@ -0,0 +1,40 @@
+using Content.Shared.Mobs;
+using Content.Shared.FixedPoint;
+using Robust.Shared.Serialization.TypeSerializers.Implementations.Custom;
+using Robust.Shared.GameStates;
+
+namespace Content.Shared.Damage.Components;
+
+/// <summary>
+/// Passively damages the entity on a specified interval.
+/// </summary>
+[RegisterComponent, NetworkedComponent]
+public sealed partial class PassiveDamageComponent : Component
+{
+    /// <summary>
+    /// The entitys' states that passive damage will apply in
+    /// </summary>
+    [DataField, ViewVariables(VVAccess.ReadWrite)]
+    public List<MobState> AllowedStates = new();
+
+    /// <summary>
+    /// Damage / Healing per interval dealt to the entity every interval
+    /// </summary>
+    [DataField, ViewVariables(VVAccess.ReadWrite)]
+    public DamageSpecifier Damage = new();
+
+    /// <summary>
+    /// Delay between damage events in seconds
+    /// </summary>
+    [DataField, ViewVariables(VVAccess.ReadWrite)]
+    public float Interval = 1f;
+
+    /// <summary>
+    /// The maximum HP the damage will be given to. If 0, disabled.
+    /// </summary>
+    [DataField, ViewVariables(VVAccess.ReadWrite)]
+    public FixedPoint2 DamageCap = 0;
+
+    [DataField("nextDamage", customTypeSerializer: typeof(TimeOffsetSerializer)), ViewVariables(VVAccess.ReadWrite)]
+    public TimeSpan NextDamage = TimeSpan.Zero;
+}