Stack System Cleanup (#38872)

* eye on the prize

* OnStackInteractUsing, TryMergeStacks, TryMergeToHands, TryMergeToContacts

* namespace

* Use, get count, getMaxCount

* component access

* add regions, mark TODO

* obsolete TryAdd, public TryMergeStacks

* GetMaxCount

* event handlers

* event handlers

* SetCount

* client server event handlers

* move to shared

* Revert "move to shared"

This reverts commit 45540a2d6b8e1e6d2a8f83a584267776c7edcd73.

* misc changes to shared

* split

* spawn and SpawnNextToOrDrop

* SpawnMultipleAtPosition, SpawnMultipleNextToOrDrop, CalculateSpawns, general server cleanup

* Rename Use to TryUse.

* Small misc changes

* Remove obsolete functions

* Remove some SetCount calls

* Partialize

* small misc change

* don't nuke the git dif with the namespace block

* Comments and reordering

* touchup to UpdateLingering

* Summary comment for StackStatusControl

* Last pass

* Actual last pass (for now)

* I know myself too well

* fixup

* goodbye lingering

* fixes

* review

* fix test

* second look

* fix test

* forgot

* remove early comp getting

---------

Co-authored-by: iaada <iaada@users.noreply.github.com>
Co-authored-by: slarticodefast <161409025+slarticodefast@users.noreply.github.com>

Content.Server/Store/Systems/StoreSystem.Ui.cs

@@ -313,7 +313,7 @@ public sealed partial class StoreSystem
         {
             var cashId = proto.Cash[value];
             var amountToSpawn = (int) MathF.Floor((float) (amountRemaining / value));
-            var ents = _stack.SpawnMultiple(cashId, amountToSpawn, coordinates);
+            var ents = _stack.SpawnMultipleAtPosition(cashId, amountToSpawn, coordinates);
             if (ents.FirstOrDefault() is {} ent)
                 _hands.PickupOrDrop(buyer, ent);
             amountRemaining -= value * amountToSpawn;