Add a news app: coach_manager authoring, team tagging, photos, editor release flow

News and NewsPhoto (team-tagged instead of categorised, one photo taggable
as main via a partial unique constraint), gated per club/services/access.py:
any current-season coach_manager, EDITOR, or ADMIN can draft and edit a news
item; only EDITOR/ADMIN can publish it, or edit it once it's live. Publishing
takes a date so it can be scheduled ahead of time rather than only right now.

Authoring/release only for now -- no member-facing reading page or public API
yet, the visibility field (internal/external/both) is there for when those land.

news/tests.py

@@ -0,0 +1,100 @@
+import datetime
+
+from django.core.files.uploadedfile import SimpleUploadedFile
+from django.db import IntegrityError
+from django.test import TestCase
+from django.utils import timezone
+
+from club.models import Club
+
+from .models import News, NewsPhoto
+
+
+def make_photo(news_item, *, is_main=False):
+    image = SimpleUploadedFile("photo.jpg", b"fake-image-bytes", content_type="image/jpeg")
+    return NewsPhoto.objects.create(news_item=news_item, image=image, is_main=is_main)
+
+
+class NewsModelTests(TestCase):
+    def setUp(self):
+        self.club = Club.objects.create(name="Ajax United", slug="ajax-united")
+
+    def test_slug_is_derived_from_title(self):
+        item = News.objects.create(club=self.club, title="Season Kickoff", body="Body text.")
+
+        self.assertEqual(item.slug, "season-kickoff")
+
+    def test_slug_is_unique_per_club_not_globally(self):
+        News.objects.create(club=self.club, title="Season Kickoff", body="First.")
+        second = News.objects.create(club=self.club, title="Season Kickoff", body="Second.")
+
+        self.assertEqual(second.slug, "season-kickoff-2")
+
+    def test_two_clubs_can_share_the_same_slug(self):
+        other_club = Club.objects.create(name="Rival FC", slug="rival-fc")
+        News.objects.create(club=self.club, title="Season Kickoff", body="First.")
+
+        other = News.objects.create(club=other_club, title="Season Kickoff", body="Other club.")
+
+        self.assertEqual(other.slug, "season-kickoff")
+
+    def test_defaults_to_draft_and_internal(self):
+        item = News.objects.create(club=self.club, title="Draft item", body="Body.")
+
+        self.assertEqual(item.status, News.Status.DRAFT)
+        self.assertEqual(item.visibility, News.Visibility.INTERNAL)
+        self.assertIsNone(item.published_at)
+
+    def test_publish_defaults_the_publish_date_to_now(self):
+        item = News.objects.create(club=self.club, title="Item", body="Body.")
+
+        item.publish()
+
+        self.assertEqual(item.status, News.Status.PUBLISHED)
+        self.assertIsNotNone(item.published_at)
+        self.assertFalse(item.is_scheduled)
+
+    def test_publish_accepts_a_future_date_and_is_scheduled(self):
+        item = News.objects.create(club=self.club, title="Item", body="Body.")
+        future = timezone.now() + datetime.timedelta(days=7)
+
+        item.publish(at=future)
+
+        self.assertEqual(item.status, News.Status.PUBLISHED)
+        self.assertEqual(item.published_at, future)
+        self.assertTrue(item.is_scheduled)
+
+    def test_unpublish_clears_the_publish_date(self):
+        item = News.objects.create(club=self.club, title="Item", body="Body.")
+        item.publish()
+
+        item.unpublish()
+
+        self.assertEqual(item.status, News.Status.DRAFT)
+        self.assertIsNone(item.published_at)
+
+
+class NewsPhotoModelTests(TestCase):
+    def setUp(self):
+        self.club = Club.objects.create(name="Ajax United", slug="ajax-united")
+        self.item = News.objects.create(club=self.club, title="Match report", body="Body.")
+
+    def test_a_second_main_photo_is_rejected_at_the_database_level(self):
+        make_photo(self.item, is_main=True)
+
+        with self.assertRaises(IntegrityError):
+            make_photo(self.item, is_main=True)
+
+    def test_two_non_main_photos_are_fine(self):
+        make_photo(self.item, is_main=False)
+        make_photo(self.item, is_main=False)
+
+        self.assertEqual(self.item.photos.count(), 2)
+
+    def test_two_different_news_items_can_each_have_a_main_photo(self):
+        other_item = News.objects.create(club=self.club, title="Other item", body="Body.")
+
+        make_photo(self.item, is_main=True)
+        make_photo(other_item, is_main=True)
+
+        self.assertEqual(NewsPhoto.objects.filter(is_main=True).count(), 2)