fix(sdks): java demo PLAYER_FIELDS 字符串拼接转义错误导致编译失败

CI javac 报 illegal character: java 字符串常量拼接被错误转义,
改为规范的分行 + 拼接写法, 本地 javac 验证通过。

Author: cuihairu

sdks/java/examples/game-demo/src/main/java/com/croupier/sdk/examples/GameDemo.java

@@ -537,7 +537,9 @@ private static void enrichDescriptor(FunctionDescriptor desc) {
     private static final String OBJ = "{\"type\":\"object\"}";
     private static final String STR = "{\"type\":\"string\"}";
     private static final String INT = "{\"type\":\"integer\"}";
-    private static final String PLAYER_FIELDS = "{\"id\":\" + STR + \",\"name\":\" + STR + \",\"level\":\" + INT + \",\"vip\":\" + INT + \",\"gold\":\" + INT + \",\"status\":\" + STR + \",\"server\":\" + STR + \",\"profile\":\"\" + OBJ + "\"}";
+    private static final String PLAYER_FIELDS =
+        "{\"id\":" + STR + ",\"name\":" + STR + ",\"level\":" + INT + ",\"vip\":" + INT
+            + ",\"gold\":" + INT + ",\"status\":" + STR + ",\"server\":" + STR + ",\"profile\":" + OBJ + "}";
 
     private static final Map<String, String[]> SCHEMAS = Map.ofEntries(
         Map.entry("player.create", new String[]{