HandsSystem Refactor (#38438)

* checkpoint

* pt 2

* pt... i forgot

* pt 4

* patch

* More test fixes

* optimization!!!

* the REAL hand system

* fix RetractableItemActionSystem.cs oversight

* the review

* test

* remove test usage of body prototype

* Update Content.IntegrationTests/Tests/Interaction/InteractionTest.cs

Co-authored-by: Tayrtahn <tayrtahn@gmail.com>

* hellcode

* hellcode 2

* Minor cleanup

* test

* Chasing the last of the bugs

* changes

---------

Co-authored-by: Tayrtahn <tayrtahn@gmail.com>

Content.Shared/Weapons/Melee/SharedMeleeWeaponSystem.cs

@@ -12,6 +12,7 @@ using Content.Shared.Database;
 using Content.Shared.FixedPoint;
 using Content.Shared.Hands;
 using Content.Shared.Hands.Components;
+using Content.Shared.Hands.EntitySystems;
 using Content.Shared.IdentityManagement;
 using Content.Shared.Interaction;
 using Content.Shared.Inventory;
@@ -51,6 +52,7 @@ public abstract class SharedMeleeWeaponSystem : EntitySystem
     [Dependency] protected readonly ISharedAdminLogManager AdminLogger = default!;
     [Dependency] protected readonly ActionBlockerSystem Blocker = default!;
     [Dependency] protected readonly DamageableSystem Damageable = default!;
+    [Dependency] private   readonly SharedHandsSystem _hands = default!;
     [Dependency] private   readonly InventorySystem _inventory = default!;
     [Dependency] private   readonly MeleeSoundSystem _meleeSound = default!;
     [Dependency] protected readonly MobStateSystem MobState = default!;
@@ -288,15 +290,14 @@ public abstract class SharedMeleeWeaponSystem : EntitySystem
         }
 
         // Use inhands entity if we got one.
-        if (EntityManager.TryGetComponent(entity, out HandsComponent? hands) &&
-            hands.ActiveHandEntity is { } held)
+        if (_hands.TryGetActiveItem(entity, out var held))
         {
             // Make sure the entity is a weapon AND it doesn't need
             // to be equipped to be used (E.g boxing gloves).
             if (EntityManager.TryGetComponent(held, out melee) &&
                 !melee.MustBeEquippedToUse)
             {
-                weaponUid = held;
+                weaponUid = held.Value;
                 return true;
             }
 
@@ -858,9 +859,9 @@ public abstract class SharedMeleeWeaponSystem : EntitySystem
 
         EntityUid? inTargetHand = null;
 
-        if (targetHandsComponent?.ActiveHand is { IsEmpty: false })
+        if (_hands.TryGetActiveItem(target.Value, out var activeHeldEntity))
         {
-            inTargetHand = targetHandsComponent.ActiveHand.HeldEntity!.Value;
+            inTargetHand = activeHeldEntity.Value;
         }
 
         var attemptEvent = new DisarmAttemptEvent(target.Value, user, inTargetHand);