refactor(src/notifications): batch‑fetch reminder logs to avoid per‑user DB queries

Reduce DB round‑trips when checking already‑sent deadline reminders, improving performance and simplifying query logic.

src/notifications/email_utils.py

@@ -188,11 +188,20 @@ def process_deadline_reminders(ticket=None):
         if t.created_by and t.created_by not in assignees:
             assignees.append(t.created_by)
 
+        # Batch-fetch existing reminder logs for this ticket's assignees
+        existing_logs = set()
+        if assignees:
+            logs_qs = DeadlineReminderLog.objects.filter(
+                ticket=t,
+                user__in=assignees,
+                days_before__in=REMINDER_DAYS,
+            ).values_list("user_id", "days_before")
+            existing_logs = {(uid, db) for uid, db in logs_qs}
+
         for user in assignees:
             if not user.email:
                 continue
 
-            # Respect user email preference
             if (
                 hasattr(user, "receive_deadline_emails")
                 and not user.receive_deadline_emails
@@ -203,13 +212,7 @@ def process_deadline_reminders(ticket=None):
 
             for days_before in REMINDER_DAYS:
                 if days_until_due == days_before:
-                    already_sent = DeadlineReminderLog.objects.filter(
-                        ticket=t,
-                        user=user,
-                        days_before=days_before,
-                    ).exists()
-
-                    if already_sent:
+                    if (user.id, days_before) in existing_logs:
                         continue
 
                     send_deadline_reminder_email(user, t, days_before)

src/notifications/views.py

@@ -1,5 +1,3 @@
-import json
-
 from django.utils import timezone
 from rest_framework import generics, permissions, status
 from rest_framework.decorators import api_view, permission_classes
@@ -71,12 +69,7 @@ def subscribe_push_view(request):
 @api_view(["POST"])
 @permission_classes([permissions.IsAuthenticated])
 def unsubscribe_push_view(request):
-    try:
-        data = json.loads(request.body)
-    except json.JSONDecodeError:
-        return Response({"error": "Invalid JSON"}, status=status.HTTP_400_BAD_REQUEST)
-
-    endpoint = data.get("endpoint")
+    endpoint = request.data.get("endpoint")
     if not endpoint:
         return Response(
             {"error": "endpoint required"}, status=status.HTTP_400_BAD_REQUEST