Add grants_waiting_list_update deadline type

Replace the awkward filtering by custom type with name matching for
grants waiting list update deadlines with a proper dedicated deadline type.

- Add `grants_waiting_list_update` to Deadline.TYPES enum
- Update `_send_grant_waiting_list_email` to filter by new type
- Add migration to convert existing custom deadlines with name
  "Update Grants in Waiting List" to the new type
- Update CLAUDE.md to specify Docker-based development commands

Author: estyxx

CLAUDE.md

@@ -79,3 +79,21 @@ The project uses Docker Compose for local development with services:
 - Test configuration uses separate settings (`pycon.settings.test`)
 - Ruff handles both linting and formatting for Python code
 - Biome handles linting and formatting for JavaScript/TypeScript
+
+## Local Development
+
+**IMPORTANT**: When running locally, all Python/Django commands must run inside Docker. The local virtual environment will not work.
+
+Use `docker exec pycon-backend-1` (without `-t` flag for non-interactive/script usage, with `-it` for interactive terminal).
+
+- **Start services**: `docker-compose up` (starts all services)
+- **Run tests**: `docker exec pycon-backend-1 uv run pytest -l -s -vvv`
+- **Single test**: `docker exec pycon-backend-1 uv run pytest path/to/test_file.py::test_function -l -s -vvv`
+- **Lint/format**: `docker exec pycon-backend-1 uv run ruff check` and `docker exec pycon-backend-1 uv run ruff format`
+- **Type checking**: `docker exec pycon-backend-1 uv run mypy .`
+- **Django management**: `docker exec pycon-backend-1 uv run python manage.py <command>`
+- **Migrations**: `docker exec pycon-backend-1 uv run python manage.py makemigrations` and `docker exec pycon-backend-1 uv run python manage.py migrate`
+
+**Troubleshooting**: If the backend container is not working:
+1. Restart container: `docker restart pycon-backend-1`
+2. If dependencies changed: Remove `backend/.venv` and rebuild with `docker-compose build --no-cache && docker-compose up`

backend/conferences/migrations/0057_add_grants_waiting_list_update_deadline_type.py

@@ -0,0 +1,56 @@
+# Generated by Django 5.1.4 on 2026-01-28
+
+from django.db import migrations, models
+
+
+def convert_custom_deadlines_to_grants_waiting_list_update(apps, schema_editor):
+    """
+    Convert existing custom deadlines with name containing
+    'Update Grants in Waiting List' to the new grants_waiting_list_update type.
+    """
+    Deadline = apps.get_model("conferences", "Deadline")
+
+    # Update custom deadlines that have "Update Grants in Waiting List" in their name
+    Deadline.objects.filter(
+        type="custom", name__contains={"en": "Update Grants in Waiting List"}
+    ).update(type="grants_waiting_list_update")
+
+
+def revert_grants_waiting_list_update_to_custom(apps, schema_editor):
+    """
+    Revert grants_waiting_list_update deadlines back to custom type.
+    """
+    Deadline = apps.get_model("conferences", "Deadline")
+    Deadline.objects.filter(type="grants_waiting_list_update").update(type="custom")
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("conferences", "0056_conference_max_proposals"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="deadline",
+            name="type",
+            field=models.CharField(
+                choices=[
+                    ("cfp", "Call for proposal"),
+                    ("voting", "Voting"),
+                    ("refund", "Ticket refund"),
+                    ("grants", "Grants"),
+                    ("badge_preview", "Badge preview"),
+                    ("invitation_letter_request", "Invitation letter request"),
+                    ("grants_waiting_list_update", "Grants waiting list update"),
+                    ("custom", "Custom deadline"),
+                ],
+                max_length=256,
+                verbose_name="type",
+            ),
+        ),
+        migrations.RunPython(
+            convert_custom_deadlines_to_grants_waiting_list_update,
+            revert_grants_waiting_list_update_to_custom,
+        ),
+    ]

backend/conferences/models/deadline.py

@@ -23,6 +23,7 @@ class Deadline(TimeFramedModel):
         ("grants", _("Grants")),
         ("badge_preview", _("Badge preview")),
         ("invitation_letter_request", _("Invitation letter request")),
+        ("grants_waiting_list_update", _("Grants waiting list update")),
         ("custom", _("Custom deadline")),
     )
 

backend/grants/tasks.py

@@ -137,7 +137,7 @@ def _send_grant_waiting_list_email(grant_id, template_identifier):
     reply_url = urljoin(settings.FRONTEND_URL, "/grants/reply/")
 
     deadline = grant.conference.deadlines.filter(
-        type="custom", name__contains={"en": "Update Grants in Waiting List"}
+        type="grants_waiting_list_update"
     ).first()
 
     _new_send_grant_email(

backend/grants/tests/test_tasks.py

@@ -70,11 +70,7 @@ def test_send_grant_reply_waiting_list_email(settings, sent_emails):
     DeadlineFactory(
         start=datetime(2023, 3, 1, 23, 59, tzinfo=timezone.utc),
         conference=conference,
-        type="custom",
-        name={
-            "en": "Update Grants in Waiting List",
-            "it": "Update Grants in Waiting List",
-        },
+        type="grants_waiting_list_update",
     )
     grant = GrantFactory(conference=conference, user=user)
 
@@ -432,11 +428,7 @@ def test_send_grant_reply_waiting_list_update_email(settings, sent_emails):
     DeadlineFactory(
         conference=grant.conference,
         start=datetime(2023, 3, 1, 23, 59, tzinfo=timezone.utc),
-        type="custom",
-        name={
-            "en": "Update Grants in Waiting List",
-            "it": "Update Grants in Waiting List",
-        },
+        type="grants_waiting_list_update",
     )
     conference_name = grant.conference.name.localize("en")