linting done now fix unit tests

src/services/db/user.db.ts

@@ -172,12 +172,15 @@ export class UserRepository {
    * @returns A promise that resolves to the user object (id, email, password_hash) or undefined if not found.
    */
   // prettier-ignore
-  async findUserWithPasswordHashById(userId: string, logger: Logger): Promise<{ user_id: string; email: string; password_hash: string | null } | undefined> {
+  async findUserWithPasswordHashById(userId: string, logger: Logger): Promise<{ user_id: string; email: string; password_hash: string | null }> {
     try {
       const res = await this.db.query<{ user_id: string; email: string; password_hash: string | null }>(
         'SELECT user_id, email, password_hash FROM public.users WHERE user_id = $1',
         [userId]
       );
+      if (res.rowCount === 0) {
+        throw new NotFoundError(`User with ID ${userId} not found.`);
+      }
       return res.rows[0];
     } catch (error) {
       logger.error({ err: error, userId }, 'Database error in findUserWithPasswordHashById');