Apply ruff formatting and fix unused import linting errors

Remove unused imports flagged by ruff (F401), apply ruff format across all
files, and restore members.signals side-effect import with noqa: F401 so the
post_save signal that auto-creates Member profiles continues to fire.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

members/migrations/0006_member_notes.py

@@ -4,15 +4,14 @@ from django.db import migrations, models
 
 
 class Migration(migrations.Migration):
-
     dependencies = [
-        ('members', '0005_remove_member_family_member_family_members'),
+        ("members", "0005_remove_member_family_member_family_members"),
     ]
 
     operations = [
         migrations.AddField(
-            model_name='member',
-            name='notes',
-            field=models.TextField(blank=True, null=True, verbose_name='notes'),
+            model_name="member",
+            name="notes",
+            field=models.TextField(blank=True, null=True, verbose_name="notes"),
         ),
     ]