refactor: fold hand-written serializable property setters into field hooks (#2587)

## Summary

Folds **113** hand-written `[SerializableProperty]` members into plain `[SerializableField]` declarations using the v4 setter hooks — value coercion/vetoes via `allowFieldChange`, post-change side effects via `fieldChanged` (whose `oldValue` parameter covers the old-house/old-sender unsubscribe patterns). Net **-450 lines** of setter boilerplate.

```cs
// before
[SerializableProperty(1)]
[CommandProperty(AccessLevel.GameMaster)]
public int Charges
{
    get => _charges;
    set
    {
        _charges = Math.Clamp(value, 0, MaxCharges);
        InvalidateProperties();
        this.MarkDirty();
    }
}

// after
[SerializableField(1, allowFieldChange: nameof(AllowChargesChange))]
[SerializedCommandProperty(AccessLevel.GameMaster)]
[InvalidateProperties]
private int _charges;

private bool AllowChargesChange(ref int value)
{
    value = Math.Clamp(value, 0, MaxCharges);
    return true;
}
```

## How sites were selected

A classifier parsed all 204 `[SerializableProperty]` sites and converted only those matching strict shapes: getter is exactly `get => _field;`, the assignment comes first (after at most an equality guard), and relocated side effects contain no `return`, no `value` mutation, and no field re-assignment. Everything else was left alone deliberately:

- **~34 custom getters** (fallback defaults like `_x == -1 ? Default : _x`, self-healing refs) — no setter hook can express these.
- **~35 pre-assignment logic** (durability Unscale/Scale sandwiches, old-state captures like PotionKeg's pile weight).
- **virtual/override members, name-mismatched backing fields (`m_`), exotic semantics** (guards' `Focus` does work on *equal* assignment; `ChampionSpawn.Active` never assigns its field).

Five sites the classifier refused were converted by hand where the hooks fit cleanly: `ReceiverCrystal.Sender`, `PlayerVendor.House`, `PlayerBarkeeper.House` (old-value unsubscribe via `oldValue`), `BaseSuit.AccessLevel` (its existing virtual `OnAccessLevelChanged` already had the exact callback shape), and `DyeTub.DyedHue` (a true veto: `AllowDyedHueChange(ref int value) => _redyable`).

## Verification

- Build: **0 errors, 0 warnings**.
- **Schema regeneration produces zero Migrations changes** — the conversion is wire- and schema-neutral by construction (same orders, types, and property names), and CI's schema diff check enforces it.
- **835 + 708 tests green.**

## Behavioral notes (all strict improvements, called out for review)

- Generated setters skip everything when the incoming value equals the current one; a few converted setters previously re-ran side effects on equal assignment (redundant `Update()`-style refreshes).
- Generated setters always `MarkDirty()` on change; several converted setters never did (e.g. `DyeTub.DyedHue`, `MorphItem` ranges) — their changes only persisted if something else dirtied the entity. Those latent persistence bugs are fixed by construction.

Projects/UOContent/Items/Misc/CommunicationCrystals.cs

@@ -275,8 +275,16 @@ public partial class BroadcastCrystal : Item
 [SerializationGenerator(0)]
 public partial class ReceiverCrystal : Item
 {
+    [SerializableField(0, fieldChanged: nameof(OnSenderChanged))]
+    [SerializedCommandProperty(AccessLevel.GameMaster)]
     private BroadcastCrystal _sender;
 
+    private void OnSenderChanged(BroadcastCrystal oldValue, BroadcastCrystal newValue)
+    {
+        oldValue?.RemoveReceiver(this);
+        newValue?.AddReceiver(this);
+    }
+
     [Constructible]
     public ReceiverCrystal() : base(0x1ED0) => Light = LightType.Circle150;
 
@@ -297,20 +305,6 @@ public partial class ReceiverCrystal : Item
         }
     }
 
-    [SerializableProperty(0, useField: nameof(_sender))]
-    [CommandProperty(AccessLevel.GameMaster)]
-    public BroadcastCrystal Sender
-    {
-        get => _sender;
-        set
-        {
-            _sender?.RemoveReceiver(this);
-            _sender = value;
-            value?.AddReceiver(this);
-            this.MarkDirty();
-        }
-    }
-
     public override void GetProperties(IPropertyList list)
     {
         base.GetProperties(list);

Projects/UOContent/Items/Misc/MorphItem.cs

@@ -30,20 +30,24 @@ public partial class MorphItem : Item
         _outsideRange = outRange;
     }
 
-    [SerializableProperty(0)]
-    [CommandProperty(AccessLevel.GameMaster)]
-    public int OutsideRange
+    [SerializableField(0, allowFieldChange: nameof(AllowOutsideRangeChange))]
+    [SerializedCommandProperty(AccessLevel.GameMaster)]
+    private int _outsideRange;
+
+    private bool AllowOutsideRangeChange(ref int value)
     {
-        get => _outsideRange;
-        set => _outsideRange = Math.Clamp(value, 0, 18);
+        value = Math.Clamp(value, 0, 18);
+        return true;
     }
 
-    [SerializableProperty(3)]
-    [CommandProperty(AccessLevel.GameMaster)]
-    public int InsideRange
+    [SerializableField(3, allowFieldChange: nameof(AllowInsideRangeChange))]
+    [SerializedCommandProperty(AccessLevel.GameMaster)]
+    private int _insideRange;
+
+    private bool AllowInsideRangeChange(ref int value)
     {
-        get => _insideRange;
-        set => _insideRange = Math.Clamp(value, 0, 18);
+        value = Math.Clamp(value, 0, 18);
+        return true;
     }
 
     [CommandProperty(AccessLevel.GameMaster)]

Projects/UOContent/Items/Misc/WarningItem.cs

@@ -14,8 +14,16 @@ public partial class WarningItem : Item
     private TextDefinition _warningMessage;
 
     // Field 1
+    [SerializableField(1, allowFieldChange: nameof(AllowRangeChange))]
+    [SerializedCommandProperty(AccessLevel.GameMaster)]
     private int _range;
 
+    private bool AllowRangeChange(ref int value)
+    {
+        value = Math.Min(value, 18);
+        return true;
+    }
+
     [SerializableField(2)]
     private TimeSpan _resetDelay;
 
@@ -39,18 +47,6 @@ public partial class WarningItem : Item
         _range = Math.Min(range, 18);
     }
 
-    [CommandProperty(AccessLevel.GameMaster)]
-    [SerializableProperty(1, useField: nameof(_range))]
-    public int Range
-    {
-        get => _range;
-        set
-        {
-            _range = Math.Min(value, 18);
-            this.MarkDirty();
-        }
-    }
-
     public virtual bool OnlyToTriggerer => false;
     public virtual int NeighborRange => 5;