feat: add AddFileReferenceRequest model

Author: SrishJ23

src/main/java/com/crowdin/client/filereferences/model/AddFileReferenceRequest.java

@@ -0,0 +1,13 @@
+package com.crowdin.client.filereferences.model;
+
+import lombok.Data;
+
+/**
+ * Request body for creating a new File Reference.
+ */
+@Data
+public class AddFileReferenceRequest {
+    private String name;     // Name of the reference
+    private String type;     // Type of the reference (e.g., "file" or "asset")
+    private Long fileId;     // ID of the file this reference points to
+}