refactor: restructure project architecture

internal/config/config.go

@@ -0,0 +1,35 @@
+package config
+
+import (
+	"log"
+	"os"
+	"strconv"
+
+	"github.com/joho/godotenv"
+)
+
+func init() {
+	if _, err := os.Stat(".env"); err == nil {
+		if err := godotenv.Load(".env"); err != nil {
+			log.Printf("Warning: Failed to load .env file: %s", err)
+		}
+	}
+}
+
+func Getenv(key, defaultValue string) string {
+	val := os.Getenv(key)
+	if val == "" {
+		val = defaultValue
+	}
+
+	return val
+}
+
+func GetBufferSize() int {
+	sizeStr := Getenv("BUFFER_SIZE", "32768")
+	size, err := strconv.Atoi(sizeStr)
+	if err != nil || size < 4096 || size > 1048576 {
+		return 32768
+	}
+	return size
+}