Add a reusable notification system; wire it into news publishing

New `notifications` app: Notification (club-scoped, keyed to the
member it's about, generic `source` via a ContentType/object_id pair
so future activities can reuse this without a new model each time)
plus notify_members(), which resolves each member's own email (if
they hold a login) and every parent/guardian's, always -- a child
with their own account doesn't opt their parents out -- and emails
the club-branded template to whichever addresses that resolves to.
Delivery is email-only for now (no in-app feed exists yet); the row
is created either way, ready for one later.

news.tasks.notify_news_published resolves the audience (a team-scoped
item's current rosters, or every active member if it's club-wide) and
calls notify_members with the item's title/plain-text body.
NewsPublishForm gained a "Notify linked members" checkbox (opt-in,
default off); when checked, NewsPublishView schedules the task with
Celery's `eta` set to the item's own published_at -- a scheduled
item's notification arrives when it actually goes live, and an
immediate publish (eta in the past) just runs right away, no separate
branch needed.

Registered the new notification email on the Club identity page's
Email tab alongside the others.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01ECGMEwrc2k4D8VQuwjstj9

news/tests.py

@@ -1,13 +1,25 @@
 import datetime
 
+from django.contrib.auth import get_user_model
+from django.core import mail
 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 club.models import Club, ClubMembership, Season
+from members.models import Member
+from notifications.models import Notification
+from teams.models import Position, Team, TeamMembership
 
 from .models import News, NewsPhoto
+from .tasks import notify_news_published
+
+User = get_user_model()
+
+
+def make_season(club, start_year=2026):
+    return Season.objects.create(club=club, start_date=datetime.date(start_year, 8, 1), end_date=datetime.date(start_year + 1, 5, 31))
 
 
 def make_photo(news_item, *, is_main=False):
@@ -121,3 +133,81 @@ class NewsPhotoModelTests(TestCase):
         make_photo(other_item, is_main=True)
 
         self.assertEqual(NewsPhoto.objects.filter(is_main=True).count(), 2)
+
+
+class NotifyNewsPublishedTests(TestCase):
+    """news.tasks.notify_news_published -- the audience is this item's teams'
+    current rosters, or every active member if it's club-wide."""
+
+    @classmethod
+    def setUpTestData(cls):
+        cls.club = Club.objects.create(name="Ajax United", slug="ajax-united")
+        cls.season = make_season(cls.club)
+        cls.position = Position.objects.create(club=cls.club, name="Player", short_name="P")
+
+    def make_member(self, first_name, *, status=ClubMembership.StatusChoices.ACTIVE, kind=ClubMembership.Kind.MEMBER, email=None):
+        member = Member.objects.create(first_name=first_name, last_name="Member", email=email or f"{first_name.lower()}@example.com")
+        if email:
+            User.objects.create_user(email=email, password="pw-secret-123")
+            member.user = User.objects.get(email=email)
+            member.save(update_fields=["user"])
+        ClubMembership.objects.create(club=self.club, member=member, season=self.season, status=status, kind=kind)
+        return member
+
+    def test_club_wide_news_notifies_every_active_member(self):
+        member = self.make_member("Jamie", email="jamie@example.com")
+        news_item = News.objects.create(club=self.club, title="Big news", body="Something happened.", status=News.Status.PUBLISHED, published_at=timezone.now())
+
+        result = notify_news_published(news_item.pk)
+
+        self.assertTrue(Notification.objects.filter(club=self.club, member=member, title="Big news").exists())
+        self.assertIn("Notified 1", result)
+
+    def test_team_scoped_news_only_notifies_that_teams_roster(self):
+        team = Team.objects.create(club=self.club, name="U16", short_name="U16")
+        other_team = Team.objects.create(club=self.club, name="U18", short_name="U18")
+        on_team = self.make_member("Jamie", email="jamie@example.com")
+        off_team = self.make_member("Alex", email="alex@example.com")
+        TeamMembership.objects.create(team=team, member=on_team, season=self.season, position=self.position)
+        TeamMembership.objects.create(team=other_team, member=off_team, season=self.season, position=self.position)
+        news_item = News.objects.create(club=self.club, title="Team news", body="Training moved.", status=News.Status.PUBLISHED, published_at=timezone.now())
+        news_item.teams.add(team)
+
+        notify_news_published(news_item.pk)
+
+        self.assertTrue(Notification.objects.filter(member=on_team).exists())
+        self.assertFalse(Notification.objects.filter(member=off_team).exists())
+
+    def test_excludes_an_inactive_member(self):
+        self.make_member("Jamie", status=ClubMembership.StatusChoices.PENDING, email="jamie@example.com")
+        news_item = News.objects.create(club=self.club, title="News", body="Body.", status=News.Status.PUBLISHED, published_at=timezone.now())
+
+        notify_news_published(news_item.pk)
+
+        self.assertFalse(Notification.objects.exists())
+
+    def test_excludes_a_guardian(self):
+        self.make_member("Alex", kind=ClubMembership.Kind.GUARDIAN, email="alex@example.com")
+        news_item = News.objects.create(club=self.club, title="News", body="Body.", status=News.Status.PUBLISHED, published_at=timezone.now())
+
+        notify_news_published(news_item.pk)
+
+        self.assertFalse(Notification.objects.exists())
+
+    def test_skips_a_news_item_that_is_no_longer_published(self):
+        news_item = News.objects.create(club=self.club, title="News", body="Body.", status=News.Status.DRAFT)
+
+        result = notify_news_published(news_item.pk)
+
+        self.assertEqual(result, "Skipped: not published.")
+        self.assertFalse(Notification.objects.exists())
+
+    def test_the_body_is_plain_text_not_markdown(self):
+        member = self.make_member("Jamie", email="jamie@example.com")
+        news_item = News.objects.create(club=self.club, title="News", body="**Bold** text.", status=News.Status.PUBLISHED, published_at=timezone.now())
+
+        notify_news_published(news_item.pk)
+
+        notification = Notification.objects.get(member=member)
+        self.assertEqual(notification.body, "Bold text.")
+        self.assertEqual(len(mail.outbox), 1)