perf(db): add targeted composite indexes

apps/workspaces/migrations/0007_workspacemembership_membership_ws_active_user_idx.py

@@ -0,0 +1,19 @@
+# Generated by Django 5.2.12 on 2026-04-30 12:23
+
+from django.conf import settings
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('workspaces', '0006_workspace_thumbnail'),
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+    ]
+
+    operations = [
+        migrations.AddIndex(
+            model_name='workspacemembership',
+            index=models.Index(fields=['workspace', 'is_active', 'user'], name='membership_ws_active_user_idx'),
+        ),
+    ]

apps/workspaces/models.py

@@ -80,6 +80,7 @@ class WorkspaceMembership(BaseModel):
         indexes = [
             models.Index(fields=["workspace"], name="membership_workspace_idx"),
             models.Index(fields=["user"], name="membership_user_idx"),
+            models.Index(fields=["workspace", "is_active", "user"], name="membership_ws_active_user_idx"),
         ]
         constraints = [
             models.UniqueConstraint(