增强字符串格式化功能，支持索引和顺序占位符

core/src/main/java/com/xujiayao/discord_mc_chat/utils/StringUtils.java

@@ -22,16 +22,50 @@ public class StringUtils {
 	}
 
 	/**
-	 * Simple {} placeholder replacement.
+	 * Formats a string with placeholders.
+	 * <p>
+	 * Supports both sequential "{}" and indexed "{0}", "{1}" placeholders.
+	 * Note: Do not mix both styles in the same string.
 	 *
-	 * @param str  String with {} placeholders
+	 * @param str  String with placeholders
 	 * @param args Arguments to replace the placeholders
 	 * @return String with placeholders replaced
 	 */
 	public static String format(String str, Object... args) {
-		for (Object arg : args) {
-			str = str.replaceFirst("\\{}", arg == null ? "null" : arg.toString().replace("\\", "\\\\"));
+		if (str == null || args == null || args.length == 0) {
+			return str;
 		}
-		return str;
+
+		// Check if the string uses indexed placeholders (e.g., "{0}", "{1}")
+		// We assume that if it contains "{0}", it's using indexed mode.
+		if (str.contains("{0}")) {
+			for (int i = 0; i < args.length; i++) {
+				String target = "{" + i + "}";
+				String replacement = args[i] == null ? "null" : args[i].toString();
+				str = str.replace(target, replacement);
+			}
+			return str;
+		}
+
+		// Otherwise, use sequential "{}" replacement
+		StringBuilder sb = new StringBuilder(str.length());
+		int searchStart = 0;
+		int argIndex = 0;
+
+		while (argIndex < args.length) {
+			int placeholderIndex = str.indexOf("{}", searchStart);
+			if (placeholderIndex == -1) {
+				break;
+			}
+
+			sb.append(str, searchStart, placeholderIndex);
+			sb.append(args[argIndex] == null ? "null" : args[argIndex].toString());
+
+			searchStart = placeholderIndex + 2;
+			argIndex++;
+		}
+
+		sb.append(str.substring(searchStart));
+		return sb.toString();
 	}
 }