fix: enforce authentication by redirecting unauthenticated users to login

internal/auth/middleware/middleware.go

@@ -2,19 +2,34 @@ package middleware
 
 import (
 	"mal/internal/domain"
+	"net/http"
 
 	"github.com/gin-gonic/gin"
 )
 
 func AuthMiddleware(svc domain.AuthService) gin.HandlerFunc {
 	return func(c *gin.Context) {
+		// Allow access to login and logout endpoints without authentication
+		if c.Request.URL.Path == "/login" || c.Request.URL.Path == "/logout" {
+			c.Next()
+			return
+		}
+
 		sessionID, err := c.Cookie("session_id")
-		if err == nil {
+		if err != nil {
+			c.Redirect(http.StatusSeeOther, "/login")
+			c.Abort()
+			return
+		}
+
 		user, err := svc.ValidateSession(c.Request.Context(), sessionID)
-			if err == nil {
+		if err != nil {
+			c.Redirect(http.StatusSeeOther, "/login")
+			c.Abort()
+			return
+		}
+
 		c.Set("User", user)
-			}
-		}
 		c.Next()
 	}
 }