feat(marketplace): seed default service categories per island

Without categories the listing form has nothing to select and provider
creation rejects unknown slugs, so the module ships with 8 baseline
categories for sao-miguel (data migration, reversible).

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: hc-sousa

src/marketplace/migrations/0002_seed_default_categories.py

@@ -0,0 +1,49 @@
+"""Seed default service categories for the São Miguel island.
+
+Without categories the listing form has nothing to select and provider
+creation rejects unknown slugs, so the module ships with a sensible baseline.
+"""
+
+from django.db import migrations
+
+DEFAULT_CATEGORIES = [
+    ('transfers', 'Transfers & Táxi', '🚐'),
+    ('tours', 'Tours & Excursões', '🗺️'),
+    ('guides', 'Guias', '🧭'),
+    ('accommodation', 'Alojamento', '🏠'),
+    ('activities', 'Atividades', '🤿'),
+    ('food', 'Restauração', '🍽️'),
+    ('rentals', 'Aluguer', '🚗'),
+    ('other', 'Outros', '✨'),
+]
+
+
+def seed_categories(apps, schema_editor):
+    Island = apps.get_model('tenancy', 'Island')
+    ServiceCategory = apps.get_model('marketplace', 'ServiceCategory')
+    for island in Island.objects.filter(key='sao-miguel'):
+        for slug, name, icon in DEFAULT_CATEGORIES:
+            ServiceCategory.objects.get_or_create(
+                island=island,
+                slug=slug,
+                defaults={'name': name, 'icon': icon},
+            )
+
+
+def remove_categories(apps, schema_editor):
+    Island = apps.get_model('tenancy', 'Island')
+    ServiceCategory = apps.get_model('marketplace', 'ServiceCategory')
+    slugs = [slug for slug, _, _ in DEFAULT_CATEGORIES]
+    for island in Island.objects.filter(key='sao-miguel'):
+        ServiceCategory.objects.filter(island=island, slug__in=slugs).delete()
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ('marketplace', '0001_initial'),
+        ('tenancy', '0008_enable_marketplace_feature_flag'),
+    ]
+
+    operations = [
+        migrations.RunPython(seed_categories, remove_categories),
+    ]