refactor(concurrency): replaced manual WaitGroup management with new wg.Go() and removed redundant code.

internal/api/handler.go

@@ -24,6 +24,7 @@ import (
 func NewHandler() *gin.Engine {
 	gin.SetMode("release")
 	r := gin.New()
+	r.Use(NoCache())
 	r.Use(ErrorHandler())
 	r.Use(ErrorLoggingMiddleware())
 
@@ -113,6 +114,15 @@ func NewHandler() *gin.Engine {
 	return r
 }
 
+func NoCache() gin.HandlerFunc {
+	return func(c *gin.Context) {
+		c.Header("Cache-Control", "no-cache, no-store, must-revalidate")
+		c.Header("Pragma", "no-cache")
+		c.Header("Expires", "0")
+		c.Next()
+	}
+}
+
 func AuthMiddleware() gin.HandlerFunc {
 	if !auth.IsEnabled() {
 		return func(c *gin.Context) {