feat: enhance localization and configuration support

- Added timezone and language settings to the environment configuration.
- Introduced built-in agent configurations with multilingual support for various agents.
- Updated Docker Compose to utilize new environment variables for timezone and language.
- Created new prompt templates for question generation, summary generation, and keywords extraction.

.env.example

@@ -14,6 +14,16 @@ GIN_MODE=release
 # 日志级别，可选值：debug, info, warn, error, fatal，默认为debug
 # LOG_LEVEL=debug
 
+# 时区设置，默认为 Asia/Shanghai
+# 影响系统时间显示和日志时间戳
+# 常用值：Asia/Shanghai, Asia/Tokyo, America/New_York, Europe/London, UTC
+TZ=Asia/Shanghai
+
+# 系统默认语言（BCP-47 格式），用于 Prompt 中 {{language}} 占位符的回退值
+# 优先级：Accept-Language 请求头 > 此环境变量 > 内置默认值 (en-US)
+# 常用值：zh-CN, en-US, ja-JP, ko-KR, ru-RU
+# WEKNORA_LANGUAGE=zh-CN
+
 # 禁止新用户注册（生产环境建议设为 true）
 DISABLE_REGISTRATION=false