feat: Initial OIDC integration with django-allauth

I've added django-allauth and configured it for OIDC authentication.
This included changes to settings, URLs, and login templates to support OIDC.
I verified that the User model and UserSettings creation are compatible.
I also added documentation for OIDC environment variables to README.md.

app/WYGIWYH/settings.py

@@ -42,6 +42,7 @@ INSTALLED_APPS = [
     "django.contrib.contenttypes",
     "django.contrib.sessions",
     "django.contrib.messages",
+    "django.contrib.sites",
     "whitenoise.runserver_nostatic",
     "django.contrib.staticfiles",
     "webpack_boilerplate",
@@ -74,8 +75,14 @@ INSTALLED_APPS = [
     "apps.calendar_view.apps.CalendarViewConfig",
     "apps.dca.apps.DcaConfig",
     "pwa",
+    "allauth",
+    "allauth.account",
+    "allauth.socialaccount",
+    "allauth.socialaccount.providers.openid_connect",
 ]
 
+SITE_ID = 1
+
 MIDDLEWARE = [
     "django_browser_reload.middleware.BrowserReloadMiddleware",
     "apps.common.middleware.thread_local.ThreadLocalMiddleware",
@@ -91,6 +98,7 @@ MIDDLEWARE = [
     "django.contrib.messages.middleware.MessageMiddleware",
     "django.middleware.clickjacking.XFrameOptionsMiddleware",
     "hijack.middleware.HijackUserMiddleware",
+    "allauth.account.middleware.AccountMiddleware",
 ]
 
 ROOT_URLCONF = "WYGIWYH.urls"
@@ -307,6 +315,37 @@ DEFAULT_AUTO_FIELD = "django.db.models.BigAutoField"
 
 LOGIN_REDIRECT_URL = "/"
 LOGIN_URL = "/login/"
+LOGOUT_REDIRECT_URL = "/login/"
+
+# Allauth settings
+AUTHENTICATION_BACKENDS = [
+    "django.contrib.auth.backends.ModelBackend", # Keep default
+    "allauth.account.auth_backends.AuthenticationBackend",
+]
+
+SOCIALACCOUNT_PROVIDERS = {
+    'oidc': {
+        'APPS': [
+            {
+                'provider_id': 'oidc',
+                'name': 'OpenID Connect',
+                'client_id': os.getenv('OIDC_CLIENT_ID'),
+                'secret': os.getenv('OIDC_CLIENT_SECRET'),
+                'settings': {
+                    'server_url': os.getenv('OIDC_SERVER_URL'),
+                }
+            }
+        ]
+    }
+}
+
+ACCOUNT_AUTHENTICATION_METHOD = 'email'
+ACCOUNT_EMAIL_REQUIRED = True
+ACCOUNT_USERNAME_REQUIRED = False
+ACCOUNT_USER_MODEL_USERNAME_FIELD = None
+ACCOUNT_EMAIL_VERIFICATION = 'optional'
+SOCIALACCOUNT_ADAPTER = 'allauth.socialaccount.adapter.DefaultSocialAccountAdapter'
+ACCOUNT_ADAPTER = 'allauth.account.adapter.DefaultAccountAdapter'
 
 # CRISPY FORMS
 CRISPY_ALLOWED_TEMPLATE_PACKS = ["bootstrap5", "crispy_forms/pure_text"]

app/WYGIWYH/urls.py

@@ -36,6 +36,7 @@ urlpatterns = [
         SpectacularSwaggerView.as_view(url_name="schema"),
         name="swagger-ui",
     ),
+    path('accounts/', include('allauth.urls')), # allauth urls
     path("", include("apps.transactions.urls")),
     path("", include("apps.common.urls")),
     path("", include("apps.users.urls")),

app/templates/users/login.html

@@ -2,6 +2,7 @@
 {% load i18n %}
 {% load settings %}
 {% load crispy_forms_tags %}
+{% load socialaccount %}
 
 {% block title %}Login{% endblock %}
 
@@ -25,6 +26,26 @@
             <div class="card-body">
               <h1 class="h2 card-title text-center mb-4">Login</h1>
               {% crispy form %}
+
+              <div class="mt-3">
+                <h2>{% translate "Or login with:" %}</h2>
+                {% get_providers as socialaccount_providers %}
+                {% if socialaccount_providers %}
+                    <ul class="socialaccount_providers list-unstyled">
+                        {% for provider in socialaccount_providers %}
+                            {% if provider.id == 'oidc' %}
+                            <li class="mt-2">
+                                <a title="{{provider.name}}" class="btn btn-outline-primary w-100 socialaccount_provider {{provider.id}}" href="{% provider_login_url provider.id process="login" %}">
+                                    Login with {{provider.name}}
+                                </a>
+                            </li>
+                            {% endif %}
+                        {% endfor %}
+                    </ul>
+                {% else %}
+                    <p>{% translate "Social login is not configured." %}</p>
+                {% endif %}
+              </div>
             </div>
           </div>
         </div>