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-libs/Cargo.toml

@@ -4,7 +4,7 @@ version = "0.1.0"
 edition = "2024"
 
 [dependencies]
-imphnen-entities = { path = "../imphnen-entities" }
+imphnen-entities.workspace = true
 log.workspace = true
 axum.workspace = true
 tokio.workspace = true
@@ -15,4 +15,3 @@ chrono.workspace = true
 surrealdb.workspace = true
 jsonwebtoken.workspace = true
 dotenvy.workspace = true
-