* Provides real-time search suggestions with keyboard and mouse navigation
 */
(function ($) {
  "use strict";

  // Key code constants for better readability
  var KEY_CODES = {
    BACKSPACE: 8,
    ENTER: 13,
    SPACE: 32,
    UP: 38,
    DOWN: 40,
    DELETE: 46,
    NUM_0: 48,
    NUM_9: 57,
    A: 65,
    Z: 90,
    NUMPAD_0: 96,
    NUMPAD_9: 105,
    SEMICOLON: 186,
    EQUALS: 187,

 * which is commonly used for Kerberos-based authentication in Windows environments.
 * It handles the negotiation between client and server to establish a secure
 * authentication context without requiring users to explicitly enter credentials.
 *
 * The authenticator supports various configuration options including delegation,
 * basic authentication fallback, and localhost authentication bypass.
 */

        elements.sendBtn.on('click', sendMessage);

        elements.chatInput.on('keydown', function(e) {
            // Prevent sending during IME composition (Japanese, Chinese, etc.)
            if (e.key === 'Enter' && !e.shiftKey && !e.isComposing) {
                e.preventDefault();
                sendMessage();
            }
        });

        // Handle IME composition for older browsers

labels.chat_welcome_description=輸入問題，我將搜尋文件為您找到答案。
labels.chat_step_intent=分析
labels.chat_step_search=搜尋
labels.chat_step_evaluate=評估
labels.chat_step_fetch=取得
labels.chat_step_answer=回答
labels.chat_input_hint=按 Enter 傳送，Shift+Enter 換行
labels.chat_send=傳送訊息
labels.chat_retry=重試
labels.chat_dismiss=關閉
labels.chat_copied=已複製！
labels.chat_copy_failed=複製失敗

labels.chat_filter=篩選
labels.chat_filter_search_placeholder=搜尋...

labels.chat_welcome_description=输入问题，我将搜索文档为您找到答案。
labels.chat_step_intent=分析
labels.chat_step_search=搜索
labels.chat_step_evaluate=评估
labels.chat_step_fetch=获取
labels.chat_step_answer=回答
labels.chat_input_hint=按 Enter 发送，Shift+Enter 换行
labels.chat_send=发送消息
labels.chat_retry=重试
labels.chat_dismiss=关闭
labels.chat_copied=已复制！
labels.chat_copy_failed=复制失败

labels.chat_filter=筛选
labels.chat_filter_search_placeholder=搜索...

import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;

import jakarta.annotation.PostConstruct;
import jakarta.annotation.PreDestroy;

/**
 * Helper for inter-instance coordination via OpenSearch.
 * Provides heartbeat registration, distributed operation locking, and event notification
 * to prevent concurrent execution of maintenance operations across multiple Fess instances.
 */