Add S3 configuration and presigned URL logic for file upload and download

app/internal/config/config.go

@@ -4,4 +4,19 @@ import "github.com/zeromicro/go-zero/rest"
 
 type Config struct {
 	rest.RestConf
+	Database DatabaseConfig
+	S3       S3Config
+}
+
+type DatabaseConfig struct {
+	DSN string
+}
+
+type S3Config struct {
+	Region                 string
+	Bucket                 string
+	AccessKeyID            string
+	SecretAccessKey        string
+	Endpoint               string `json:",optional"`     // Optional: for S3-compatible services
+	PresignedURLExpiration int64  `json:",default=3600"` // Default 1 hour
 }