Add internal temperatures for cooking meats (#20659)

Content.Server/Temperature/Components/InternalTemperatureComponent.cs

@@ -0,0 +1,48 @@
+using Content.Server.Temperature.Systems;
+
+namespace Content.Server.Temperature.Components;
+
+/// <summary>
+/// Entity has an internal temperature which conducts heat from its surface.
+/// Requires <see cref="TemperatureComponent"/> to function.
+/// </summary>
+/// <remarks>
+/// Currently this is only used for cooking but animal metabolism could use it too.
+/// Too hot? Suffering heatstroke, start sweating to cool off and increase thirst.
+/// Too cold? Suffering hypothermia, start shivering to warm up and increase hunger.
+/// </remarks>
+[RegisterComponent, Access(typeof(TemperatureSystem))]
+public sealed partial class InternalTemperatureComponent : Component
+{
+    /// <summary>
+    /// Internal temperature which is modified by surface temperature.
+    /// This gets set to <see cref="TemperatureComponent.CurrentTemperature"/> on mapinit.
+    /// </summary>
+    [DataField, ViewVariables(VVAccess.ReadWrite)]
+    public float Temperature;
+
+    /// <summary>
+    /// Thermal conductivity of the material in W/m/K.
+    /// Higher conductivity means its insides will heat up faster.
+    /// </summary>
+    [DataField, ViewVariables(VVAccess.ReadWrite)]
+    public float Conductivity = 0.5f;
+
+    /// <summary>
+    /// Average thickness between the surface and the inside.
+    /// For meats and such this is constant.
+    /// Thicker materials take longer for heat to dissipate.
+    /// </summary>
+    [DataField(required: true), ViewVariables(VVAccess.ReadWrite)]
+    public float Thickness;
+
+    /// <summary>
+    /// Surface area in m^2 for the purpose of conducting surface temperature to the inside.
+    /// Larger surface area means it takes longer to heat up/cool down
+    /// </summary>
+    /// <remarks>
+    /// For meats etc this should just be the area of the cooked surface not the whole thing as it's only getting heat from one side usually.
+    /// </remarks>
+    [DataField(required: true), ViewVariables(VVAccess.ReadWrite)]
+    public float Area;
+}