feat: replace email flows with in-app notifications

Add recipient notification detail and filtering, a queued admin composer, and contextual automatic titles. Retire email delivery, obsolete auth routes, newsletter data, and related templates and settings.

apps/users/migrations/0009_alter_user_options_and_more.py

@@ -0,0 +1,41 @@
+# Generated by Django 5.2.5 on 2026-09-26 07:57
+
+from django.db import migrations
+
+
+def align_email_identity_flags(apps, schema_editor):
+    users = apps.get_model('users', 'User').objects
+    users.filter(email__isnull=False).exclude(email='').update(is_email_verified=True)
+    users.filter(email__isnull=True).update(is_email_verified=False)
+    users.filter(email='').update(is_email_verified=False)
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('users', '0008_alter_user_managers'),
+    ]
+
+    operations = [
+        migrations.RunPython(align_email_identity_flags, migrations.RunPython.noop),
+        migrations.AlterModelOptions(
+            name='user',
+            options={'permissions': [('send_notification', 'Can send in-app notifications')], 'verbose_name': 'User', 'verbose_name_plural': 'Users'},
+        ),
+        migrations.RemoveField(
+            model_name='user',
+            name='email_verification_sent_at',
+        ),
+        migrations.RemoveField(
+            model_name='user',
+            name='email_verification_token',
+        ),
+        migrations.RemoveField(
+            model_name='user',
+            name='password_reset_token',
+        ),
+        migrations.RemoveField(
+            model_name='user',
+            name='password_reset_token_expires_at',
+        ),
+    ]