Add a news review workflow and a staff notification area

News gains a PENDING_REVIEW status between draft and published. A
non-editor author (can_add_news but not can_publish_news -- a
coach_manager, not an ADMIN/EDITOR) gets a "Send for review" button
instead of Publish; an editor/admin always sees Publish directly, no
review step. Submitting notifies every ADMIN/EDITOR in-app only (see
notify_members' new send_email=False) -- a review queue that emailed
on every submission would get noisy fast.

The notification area itself: a topbar bell (badge + dropdown, same
<details>/<summary> convention as the sidebar's user-menu, generalised
to a shared .dismissable-details close handler) visible on every page,
plus a fuller "Notifications" card on the dashboard, both fed by a new
notification_bell context processor. "Mark all read" clears the
signed-in staff member's own unread notifications for this club.

This is the reusable notification system's first consumer beyond news
publishing itself -- validates that notify_members()/Notification
generalise the way they were meant to.

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

news/migrations/0005_alter_news_status.py

@@ -0,0 +1,18 @@
+# Generated by Django 6.0.6 on 2026-08-21 07:35
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('news', '0004_news_body_en_news_title_en'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='news',
+            name='status',
+            field=models.CharField(choices=[('draft', 'draft'), ('pending_review', 'pending review'), ('published', 'published')], default='draft', max_length=20, verbose_name='status'),
+        ),
+    ]