some backend stuff for air alarms

finally, some UI states!!!

Content.Shared/Atmos/Monitor/AtmosSensorData.cs

@@ -0,0 +1,37 @@
+using Content.Shared.Atmos.Monitor.Components;
+
+namespace Content.Shared.Atmos.Monitor;
+
+public sealed class AtmosSensorData : IAtmosDeviceData
+{
+    public bool Enabled { get; set; }
+    public bool Dirty { get; set; }
+    public bool IgnoreAlarms { get; set; }
+
+    /// Most fields are readonly, because it's data that's meant to be transmitted.
+
+    /// <summary>
+    ///     Current pressure detected by this sensor.
+    /// </summary>
+    public float? Pressure { get; }
+    /// <summary>
+    ///     Current temperature detected by this sensor.
+    /// </summary>
+    public float? Temperature { get; }
+    /// <summary>
+    ///     Current amount of moles detected by this sensor.
+    /// </summary>
+    public float? TotalMoles { get; }
+    /// <summary>
+    ///     Current alarm state of this sensor. Does not reflect the highest alarm state on the network.
+    /// </summary>
+    public AtmosMonitorAlarmType AlarmState { get; }
+    /// <summary>
+    ///     Current number of gases on this sensor.
+    /// </summary>
+    public Dictionary<Gas, float> Gases { get; }
+    /// <summary>
+    ///     If this sensor is currently detecting a fire.
+    /// </summary>
+    public bool OnFire { get; }
+}