feat: 新增请求协调与统计能力，并实现配置/语言文件安全自动补全

- 新增 RequestCoordinator，请求统一走限流、冷却、排队与派发流程
- 新增 token 估算与 UsageTracker，并接入 API usage 解析（prompt/completion/total）
- 新增上下文 token 预算裁剪与可选自动总结能力
- 重构命令调用链至协调器，新增 `/chatgpt stats [reset]`，同步补全权限与补全提示
- 新增 ConfigFileUpdater：为 `config.yml` 与 `lang/*.yml` 自动补齐缺失项，保留用户已有配置与注释，并生成备份
- 修复自动补全插入顺序/空行/注释归属问题，避免重复块与空行膨胀
- 优化 `config.yml` 注释说明：保持原意，仅补充更清晰的中英文细节说明

src/main/resources/lang/en.yml

@@ -11,17 +11,28 @@ messages:
   help_context: "&e/chatgpt context - Toggle context mode."
   help_clear: "&e/chatgpt clear - Clear conversation history."
   help_character: "&e/chatgpt character [character_name] - List or switch to a character."
+  help_stats: "&e/chatgpt stats - Show token usage statistics."
   context_toggle: "&eContext is now %s."
   context_toggle_enabled: "&aenabled"
   context_toggle_disabled: "&cdisabled"
   current_model_info: "&eCurrent model: %s. Use /chatgpt model <model_name> to switch models."
   model_switch: "&aModel switched to %s"
   chatgpt_error: "&cFailed to contact ChatGPT."
+  no_api_key: "&cNo API key configured. Please set api.keys in config.yml."
   chatgpt_response: "&b%s: %s"
   question: "&bYou: %s"
+  queued: "&eYour request has been queued. Position: %s"
+  queue_full: "&cQueue is full. Please try again later."
+  queue_full_user: "&cYou have too many pending requests. Please wait."
+  cooldown: "&cYou're sending requests too fast. Please wait %s ms."
+  rate_limited: "&cRate limited. Please try again later."
+  stats_header: "&e===== MineChatGPT Stats ====="
+  stats_global: "&eGlobal tokens: %s (prompt=%s, completion=%s), requests=%s"
+  stats_user: "&eYour tokens: %s (prompt=%s, completion=%s), requests=%s"
+  stats_reset: "&aStats reset."
   character_switched: "&aSwitched to character: %s"
   available_characters: "&eAvailable characters:"
   invalid_character: "&cInvalid character. Use /chatgpt character to list available characters."
   invalid_model: "&cInvalid model. Use /chatgpt modellist to see available models."
   available_models: "&eAvailable models:"
-  no_permission: "&cYou do not have permission to use this command. Required permission: %s"
+  no_permission: "&cYou do not have permission to use this command. Required permission: %s"

src/main/resources/lang/zh.yml

@@ -11,17 +11,28 @@ messages:
   help_context: "&e/chatgpt context - 切换连续对话模式"
   help_clear: "&e/chatgpt clear - 清空对话历史"
   help_character: "&e/chatgpt character [character_name] - 列出或切换角色"
+  help_stats: "&e/chatgpt stats - 查看 token 消耗统计"
   context_toggle: "&e连续对话模式已%s。"
   context_toggle_enabled: "&a开启"
   context_toggle_disabled: "&c关闭"
   current_model_info: "&e当前模型：%s，输入 /chatgpt model <model_name> 来切换模型。"
   model_switch: "&a已切换至模型 %s"
   chatgpt_error: "&c无法联系ChatGPT。"
+  no_api_key: "&c未配置 API Key，请在 config.yml 的 api.keys 中设置。"
   chatgpt_response: "&b%s: %s"
   question: "&b你: %s"
+  queued: "&e你的请求已进入队列，当前位置：%s"
+  queue_full: "&c队列已满，请稍后再试。"
+  queue_full_user: "&c你有太多等待中的请求，请先等待。"
+  cooldown: "&c请求过快，请等待 %s 毫秒。"
+  rate_limited: "&c触发限流，请稍后再试。"
+  stats_header: "&e===== MineChatGPT 统计 ====="
+  stats_global: "&e全局 tokens：%s（prompt=%s，completion=%s），请求数=%s"
+  stats_user: "&e你的 tokens：%s（prompt=%s，completion=%s），请求数=%s"
+  stats_reset: "&a统计已重置。"
   character_switched: "&a已切换至角色： %s"
   available_characters: "&e可用的角色列表："
   invalid_character: "&c无效的角色。使用 /chatgpt character 查看所有可用的角色。"
   invalid_model: "&c模型无效。使用 /chatgpt modellist 查看可用模型。"
   available_models: "&e可用模型列表："
-  no_permission: "&c你没有权限使用这个指令。需要的权限：%s"
+  no_permission: "&c你没有权限使用这个指令。需要的权限：%s"