docs: 更新环境变量和docker-compose配置中的占位文本

将环境变量和docker-compose配置中的示例密码和密钥替换为更明确的占位文本
添加配置项的注释说明

backend/env/.env.dev

@@ -28,7 +28,7 @@ DATABASE_TYPE = "mysql"  # mysql、postgres、[qlite、dm这俩种不支持代
 DATABASE_HOST = "localhost"
 DATABASE_PORT = 3306  # MySQL:3306 PostgreSQL:5432
 DATABASE_USER = "root"
-DATABASE_PASSWORD = "yourpassword"
+DATABASE_PASSWORD = "你的数据库密码"
 DATABASE_NAME = "fastapiadmin"
 
 # Redis配置
@@ -36,13 +36,13 @@ REDIS_ENABLE = True
 REDIS_HOST = "localhost"
 REDIS_PORT = 6379
 REDIS_USER = ""
-REDIS_PASSWORD = "yourpassword"
+REDIS_PASSWORD = "你的Redis密码"
 REDIS_DB_NAME = 1
 
 # 日志配置
 LOGGER_LEVEL = "DEBUG"   # 日志级别
 
 # 大模型配置
-OPENAI_BASE_URL = "https://api.deepseek.com"
-OPENAI_API_KEY = "sk-yourapikey"
-OPENAI_MODEL = "deepseek-chat"
+OPENAI_BASE_URL = "你的大模型接口地址"
+OPENAI_API_KEY = "sk-你的大模型密钥"
+OPENAI_MODEL = "你的大模型模型"