test: migrate backend suites to pytest with module coverage gate

Split backend tests into unit and integration suites, add isolated fixtures and coverage enforcement, and update CI and test documentation. Cover current authentication, content, notification, payment, media, and admin flows; fix behaviors revealed by the new tests. Validate both suites and the per-module gate against local PostgreSQL.

apps/events/tests/unit/test_admin_actions.py

@@ -0,0 +1,34 @@
+from types import SimpleNamespace
+
+import pytest
+from django.contrib import admin
+
+from apps.events.admin import EventAdmin
+from apps.events.models import Event
+
+
+pytestmark = pytest.mark.unit
+
+
+def test_event_admin_formats_empty_price_and_capacity():
+    model_admin = EventAdmin(Event, admin.site)
+    event = SimpleNamespace(price=None, capacity=None, current_attendees_count=3, is_registration_open=True)
+    assert model_admin.price_display(event) == "رایگان"
+    assert model_admin.capacity_display(event) == "نامحدود"
+    assert model_admin.attendees_display(event) == 3
+    assert model_admin.is_registration_open_display(event)
+
+
+def test_event_admin_status_actions_update_selection(mocker):
+    model_admin = EventAdmin(Event, admin.site)
+    mocker.patch.object(model_admin, "message_user")
+    queryset = mocker.Mock()
+    queryset.count.return_value = 2
+    for action, status in (
+        (model_admin.make_published, Event.StatusChoices.PUBLISHED),
+        (model_admin.make_draft, Event.StatusChoices.DRAFT),
+        (model_admin.make_cancelled, Event.StatusChoices.CANCELLED),
+        (model_admin.make_completed, Event.StatusChoices.COMPLETED),
+    ):
+        action(SimpleNamespace(), queryset)
+        queryset.update.assert_called_with(status=status)