SPI for JSObject_id

Sources/JavaScriptKit/FundamentalObjects/JSBigInt.swift

@@ -19,7 +19,7 @@ public final class JSBigInt: JSObject {
         self.init(id: _i64_to_bigint(Int64(bitPattern: value), false))
     }
 
-    override public init(id: JavaScriptObjectRef) {
+    @_spi(JSObject_id) override public init(id: JavaScriptObjectRef) {
         super.init(id: id)
     }
 

Sources/JavaScriptKit/FundamentalObjects/JSObject.swift

@@ -16,8 +16,8 @@ import _CJavaScriptKit
 /// reference counting system.
 @dynamicMemberLookup
 public class JSObject: Equatable {
-    internal var id: JavaScriptObjectRef
-    init(id: JavaScriptObjectRef) {
+    @_spi(JSObject_id) public var id: JavaScriptObjectRef
+    @_spi(JSObject_id) public init(id: JavaScriptObjectRef) {
         self.id = id
     }