feat: initialized smtp service;

refactor: config now returns a copy of a struct to prevent editing;
chore: corrected identation

backend/internal/middleware/request.go

@@ -46,15 +46,15 @@ func UserInfoFromContext(c *gin.Context) (*UserInfo, bool) {
 	var ok bool
 
 	username, ok = c.Get("username") ; if !ok {
-     return &UserInfo{Username: "", Role: enums.GuestRole}, true
+		return &UserInfo{Username: "", Role: enums.GuestRole}, true
 	}
 
 	role, ok = c.Get("role"); if !ok {
-     return nil, false
+		return nil, false
 	}
 
 	if username == nil {
-     return &UserInfo{Username: "", Role: enums.GuestRole}, true
+		return &UserInfo{Username: "", Role: enums.GuestRole}, true
 	}
 
 	if role == nil {
@@ -103,7 +103,7 @@ func RequestMiddleware[T any](role enums.Role) gin.HandlerFunc {
 			User: *userInfo,
 			Body: body,
 		}
-		
+
 		c.Set(requestKey, request)
 		c.Next()
 	})