feat(ad_control): new AdSurface + AdPlacement module for placement-based featured/top events

- New ad_control Django app: AdSurface + AdPlacement models with GLOBAL/LOCAL scope
- Admin CRUD API at /api/v1/ad-control/ (JWT-protected): surfaces, placements, picker events
- Placement lifecycle: DRAFT → ACTIVE|SCHEDULED → EXPIRED|DISABLED
- LOCAL scope: Haversine ≤ 50km from event lat/lng (fixed radius, no config needed)
- Consumer APIs: /api/events/featured-events/ and /api/events/top-events/ rewritten
  to use placement-based queries (same URL paths + response shape — no breaking changes)
- Seed command: seed_surfaces --migrate converts existing is_featured/is_top_event booleans
- mount: admin_api/urls.py → ad-control/, mobile_api/urls.py → replaced consumer views
- settings.py: added ad_control to INSTALLED_APPS

ad_control/management/commands/seed_surfaces.py

@@ -0,0 +1,100 @@
+"""
+Seed the default AdSurface records and migrate existing boolean flags to placements.
+
+Usage:
+    python manage.py seed_surfaces          # seed surfaces only
+    python manage.py seed_surfaces --migrate # also migrate is_featured / is_top_event to placements
+"""
+from django.core.management.base import BaseCommand
+from ad_control.models import AdSurface, AdPlacement
+from events.models import Event
+
+
+SURFACES = [
+    {
+        'key': 'HOME_FEATURED_CAROUSEL',
+        'name': 'Featured Carousel',
+        'description': 'Homepage hero carousel — high-impact banner-style placement.',
+        'max_slots': 8,
+        'layout_type': 'carousel',
+        'sort_behavior': 'rank',
+    },
+    {
+        'key': 'HOME_TOP_EVENTS',
+        'name': 'Top Events',
+        'description': 'Homepage "Top Events" grid section below the hero.',
+        'max_slots': 10,
+        'layout_type': 'grid',
+        'sort_behavior': 'rank',
+    },
+]
+
+
+class Command(BaseCommand):
+    help = 'Seed default ad surfaces and optionally migrate boolean flags to placements.'
+
+    def add_arguments(self, parser):
+        parser.add_argument(
+            '--migrate',
+            action='store_true',
+            help='Also migrate existing is_featured / is_top_event flags to AdPlacement rows.',
+        )
+
+    def handle(self, *args, **options):
+        # --- Seed surfaces ---
+        for s in SURFACES:
+            obj, created = AdSurface.objects.update_or_create(
+                key=s['key'],
+                defaults=s,
+            )
+            status = 'CREATED' if created else 'EXISTS'
+            self.stdout.write(f"  [{status}] {obj.key} — {obj.name}")
+
+        # --- Migrate boolean flags ---
+        if options['migrate']:
+            self.stdout.write('\nMigrating boolean flags to placements...')
+
+            featured_surface = AdSurface.objects.get(key='HOME_FEATURED_CAROUSEL')
+            top_surface = AdSurface.objects.get(key='HOME_TOP_EVENTS')
+
+            featured_events = Event.objects.filter(is_featured=True)
+            top_events = Event.objects.filter(is_top_event=True)
+
+            created_count = 0
+
+            for rank, event in enumerate(featured_events, start=1):
+                _, created = AdPlacement.objects.get_or_create(
+                    surface=featured_surface,
+                    event=event,
+                    defaults={
+                        'status': 'ACTIVE',
+                        'priority': 'MANUAL',
+                        'scope': 'GLOBAL',
+                        'rank': rank,
+                        'boost_label': 'Featured',
+                    },
+                )
+                if created:
+                    created_count += 1
+
+            for rank, event in enumerate(top_events, start=1):
+                _, created = AdPlacement.objects.get_or_create(
+                    surface=top_surface,
+                    event=event,
+                    defaults={
+                        'status': 'ACTIVE',
+                        'priority': 'MANUAL',
+                        'scope': 'GLOBAL',
+                        'rank': rank,
+                        'boost_label': 'Top Event',
+                    },
+                )
+                if created:
+                    created_count += 1
+
+            self.stdout.write(self.style.SUCCESS(
+                f'  Migrated {created_count} placements '
+                f'({featured_events.count()} featured, {top_events.count()} top events).'
+            ))
+
+        self.stdout.write(self.style.SUCCESS('\nDone.'))