add id method back to wired-scene resources

spatial/wit/wired-scene/world.wit

@@ -17,6 +17,8 @@ interface material {
   resource material {
     constructor();
 
+    id: func() -> u32;
+
     name: func() -> string;
     set-name: func(value: string);
 
@@ -31,6 +33,8 @@ interface mesh {
   use material.{material};
 
   resource primitive {
+    id: func() -> u32;
+
     material: func() -> option<material>;
     set-material: func(value: option<borrow<material>>);
 
@@ -43,6 +47,8 @@ interface mesh {
   resource mesh {
     constructor();
 
+    id: func() -> u32;
+
     name: func() -> string;
     set-name: func(value: string);
 
@@ -63,6 +69,8 @@ interface node {
   resource node {
     constructor();
 
+    id: func() -> u32;
+
     name: func() -> string;
     set-name: func(value: string);