Salvage magnet revamp (#23119)

* Generic offering window

* More work

* weh

* Parity

* Progression meter

* magnet

* rona

* PG asteroid work

* code red

* Asteroid spawnings

* clams

* a

* Marker fixes

* More fixes

* Workings of biome asteroids

* A

* Fix this loading code

* a

* Fix masking

* weh

* Fixes

* Magnet claiming

* toe

* petogue

* magnet

* Bunch of fixes

* Fix default

* Fixes

* asteroids

* Fix offerings

* Localisation and a bunch of fixes

* a

* Fixes

* Preliminary draft

* Announcement fixes

* Fixes and bump spawn rate

* Fix asteroid spawns and UI

* More fixes

* Expeditions fix

* fix

* Gravity

* Fix announcement rounding

* a

* Offset tweak

* sus

* jankass

* Fix merge

Content.Shared/Procedural/PostGeneration/BiomeMarkerLayerPostGen.cs

@@ -0,0 +1,21 @@
+using Content.Shared.Parallax.Biomes.Markers;
+using Content.Shared.Procedural.PostGeneration;
+using Content.Shared.Random;
+using Robust.Shared.Prototypes;
+
+namespace Content.Shared.Procedural.PostGeneration;
+
+/// <summary>
+/// Spawns the specified marker layer on top of the dungeon rooms.
+/// </summary>
+public sealed partial class BiomeMarkerLayerPostGen : IPostDunGen
+{
+    /// <summary>
+    /// How many times to spawn marker layers; can duplicate.
+    /// </summary>
+    [DataField]
+    public int Count = 6;
+
+    [DataField(required: true)]
+    public ProtoId<WeightedRandomPrototype> MarkerTemplate;
+}