Add test for round-tripping dialogue library resources through scene schema

tests/serialization/scene-document-json.test.ts

@@ -73,6 +73,25 @@ describe("scene document JSON", () => {
     expect(parseSceneDocumentJson(serializedDocument)).toEqual(document);
   });
 
+  it("round-trips project dialogue library resources through the scene schema", () => {
+    const document = createEmptySceneDocument({ name: "Dialogue Scene" });
+    document.dialogues.dialogues["dialogue-bell"] = {
+      id: "dialogue-bell",
+      title: "Bell Tower",
+      lines: [
+        {
+          id: "dialogue-line-bell-1",
+          speakerName: "Watcher",
+          text: "The bell rings before dawn."
+        }
+      ]
+    };
+
+    expect(parseSceneDocumentJson(serializeSceneDocument(document))).toEqual(
+      document
+    );
+  });
+
   it("round-trips authored scheduler routines in the scene document schema", () => {
     const npc = createNpcEntity({
       id: "entity-npc-clocksmith",