feat(auth): support multiple user roles in JWT and services

- Change JWT access token RoleID claim from int to []int to support multiple roles per user
- Update all token generation and refresh logic to handle multiple role IDs as []int
- Refactor services to return and process multiple role IDs from user_roles table
- Fix OAuth state handling explanation and improve code comments
- Clean up related function signatures and usages for consistency

services/users.go

@@ -29,9 +29,9 @@ func CheckEmailInDB(email string) (bool, error) {
 
 func GetUserIDFromEmail(email string) (string, error) {
 	log.Print(email)
-	query := `SELECT user_id
+	query := `SELECT users_id
 				FROM (
-					SELECT user_id, 1 AS priority
+					SELECT users_id, 1 AS priority
 					FROM users
 					WHERE email_address = ?
 					AND is_deleted = 0