Gas pipe sensors (#33128)

* Initial commit

* Monitored pipe node is now referenced by name

* Review changes

* Simplified construction

* Tweaked deconstruction to match other binary atmos devices

* Helper function removal

* Updated attribution

Content.Server/Atmos/Monitor/Components/AtmosMonitorComponent.cs

@@ -48,7 +48,9 @@ public sealed partial class AtmosMonitorComponent : Component
     [DataField("gasThresholds")]
     public Dictionary<Gas, AtmosAlarmThreshold>? GasThresholds;
 
-    // Stores a reference to the gas on the tile this is on.
+    /// <summary>
+    /// Stores a reference to the gas on the tile this entity is on (or the pipe network it monitors; see <see cref="MonitorsPipeNet"/>).
+    /// </summary>
     [ViewVariables]
     public GasMixture? TileGas;
 
@@ -65,4 +67,19 @@ public sealed partial class AtmosMonitorComponent : Component
     /// </summary>
     [DataField("registeredDevices")]
     public HashSet<string> RegisteredDevices = new();
+
+    /// <summary>
+    /// Specifies whether this device monitors its own internal pipe network rather than the surrounding atmosphere.
+    /// </summary>
+    /// <remarks>
+    /// If 'true', the entity will require a NodeContainerComponent with one or more PipeNodes to function.
+    /// </remarks>
+    [DataField]
+    public bool MonitorsPipeNet = false;
+
+    /// <summary>
+    /// Specifies the name of the pipe node that this device is monitoring.
+    /// </summary>
+    [DataField]
+    public string NodeNameMonitoredPipe = "monitored";
 }