User Registration and Authentication

### Brief description
As a _New User_
I need _to securely create an account and log in_
So that _I can access my habit data across devices and keep it private_


### Details and Assumptions
* Users can sign up using email, social media, or phone number.
* Passwords must be stored securely using encryption.
* Users can reset their password if forgotten.
* Authentication should support OAuth for third-party login

### Acceptance Criteria

```gherkin
Given I am a new user
When I sign up for the app
Then I should be able to create an account using email or a social media account
```

```gherkin
Given I already have an account
When I log in
Then I should be able to securely access my account with my credentials
```

```gherkin
Given I forgot my password
When I request a password reset
Then I should receive an email or message to reset it securely
```