refactor(config, telegram_bot): Simplify GPTMail API key configuration and remove redundant Telegram enabled flag

- Simplify GPTMail API key initialization logic by removing separate api_key and api_keys variables and consolidating into single line with fallback to ["gpt-test"]
- Update config.toml.example to use api_keys list format instead of deprecated api_key single value
- Remove TELEGRAM_ENABLED configuration variable and related check from telegram_bot.py
- Simplify Telegram Bot startup validation to only check for bot_token and admin_chat_ids
- Update default auth_provider from "cpa" to "s2a" in config.toml.example
- Improve documentation comments in config.toml.example for GPTMail domains and CRS service
- Localize error messages in telegram_bot.py to Chinese for consistency
- Streamline configuration by removing unnecessary intermediate variables and checks

config.toml.example

@@ -12,8 +12,8 @@ email_provider = "gptmail"
 # 选择使用的授权服务: "crs" / "cpa" / "s2a"
 #   - crs: 原有 CRS 系统，需手动添加账号到 CRS
 #   - cpa: CPA (Codex/Copilot Authorization) 系统，后台自动处理账号
-#   - s2a: Sub2API 系统，支持 OAuth 授权和账号入库
-auth_provider = "cpa"
+#   - s2a: Sub2API 系统，支持 OAuth 授权和账号入库 (推荐)
+auth_provider = "s2a"
 
 # 是否将 team.json 中的 Team Owner 也添加到授权服务
 # 开启后，运行时会自动将 team.json 中的 Owner 账号也进行授权入库
@@ -67,20 +67,14 @@ web_url = "https://your-email-service.com"
 # API 接口地址
 api_base = "https://mail.chatgpt.org.uk"
 
-# API 密钥配置 (支持两种方式)
-# 方式1: 单个 Key (兼容旧配置)
-api_key = "gpt-test"
-
-# 方式2: 多个 Key 轮询 (推荐，可分散请求限制)
-# api_keys = ["key1", "key2", "key3"]
-
-# 注意: 也可以通过 Telegram Bot 的 /gptmail_add 命令动态添加 Key
+# API 密钥列表 (支持多个 Key 轮询，可分散请求限制)
+# 也可以通过 Telegram Bot 的 /gptmail_add 命令动态添加 Key
+api_keys = ["gpt-test"]
 
 # 邮箱前缀 (留空则自动生成 {8位随机字符}-oaiteam 格式)
 prefix = ""
 # 可用域名列表，生成邮箱时随机选择
 # 这些域名已配置 MX 记录指向 GPTMail 服务器
-# 下面域名是可用的
 domains = [
     "29thnewport.org.uk", "2ndwhartonscoutgroup.org.uk",
     "abrahampath.org.uk", "aiccministry.com",
@@ -120,6 +114,7 @@ domains = [
 
 # ==================== CRS 服务配置 ====================
 # CRS (Central Registration Service) 用于管理注册账号的中心服务
+# 仅当 auth_provider = "crs" 时生效
 [crs]
 # CRS API 接口地址
 api_base = "https://your-crs-service.com"
@@ -213,8 +208,6 @@ tracker_file = "team_tracker.json"
 # ==================== Telegram Bot 配置 ====================
 # 通过 Telegram Bot 远程控制和监控任务
 [telegram]
-# 是否启用 Telegram Bot
-enabled = false
 # Bot Token (通过 @BotFather 创建获取)
 bot_token = "your-bot-token"
 # 授权管理员的 Chat ID 列表 (通过 @userinfobot 获取)