Add comprehensive tests for mentor repository and authentication

- Implemented tests for creating, retrieving, updating, and deleting mentors in `mentor_repository_test.rs`.
- Added tests for user authentication, including successful login, invalid email formats, and inactive users in `auth_login_tests.rs`.
- Created a mock test environment setup in `mock_test.rs` to facilitate database operations during tests.
- Updated module structure to include new test files for mentors and authentication.
- Ensured cleanup of the database after tests to maintain isolation and prevent side effects.

imphnen-backend/src/bin/seeder.rs

@@ -20,7 +20,8 @@ fn main() -> Result<(), Box<dyn Error>> {
 	run_seed("seed_roles_permissions")?;
 	run_seed("seed_users")?;
 	run_seed("seed_events")?;
-
+	run_seed("seed_gacha_rolls")?;
+	run_seed("seed_mentor_user")?;
 	println!("\n✅ All seeding completed successfully.");
 	Ok(())
 }