feat(admin): add draft task creation

admin/internal/config/config.go

@@ -15,6 +15,7 @@ const (
 	adminPasswordBcryptEnv = "CMBUYER_ADMIN_PASSWORD_BCRYPT"
 	sessionSecretEnv       = "CMBUYER_SESSION_SECRET"
 	cookieSecureEnv        = "CMBUYER_COOKIE_SECURE"
+	databaseSourceEnv      = "CMBUYER_DATABASE_SOURCE"
 	minimumSecretLength    = 32
 )
 
@@ -24,6 +25,7 @@ type Config struct {
 	AdminPasswordBcrypt string
 	SessionSecret       []byte
 	CookieSecure        bool
+	DatabaseSource      string
 }
 
 // LoadFromEnv 从进程环境读取配置。错误只指出缺失或非法的变量名，绝不回显秘密。
@@ -65,12 +67,17 @@ func Load(lookup func(string) (string, bool)) (Config, error) {
 			return Config{}, fmt.Errorf("%s must be exactly true or false", cookieSecureEnv)
 		}
 	}
+	databaseSource, err := required(lookup, databaseSourceEnv)
+	if err != nil {
+		return Config{}, err
+	}
 
 	return Config{
 		AdminUsername:       username,
 		AdminPasswordBcrypt: passwordHash,
 		SessionSecret:       []byte(secret),
 		CookieSecure:        cookieSecure,
+		DatabaseSource:      databaseSource,
 	}, nil
 }