Add phase 2: recipes with visibility, photos, search and favourites

- Recipe model with ingredients (amount/range, unit, group, note), steps,
  lowercase tags, author notes, source URL and private/public visibility
- Central RecipeQuerySet.visible_to() used by every read path; edit only
  by owner, delete by owner or admin (visible recipes only)
- Text-based editing: ingredient/step parser with roundtrip and scaling
- Photo upload (JPEG/PNG/WebP/HEIC), re-encoded to WebP without EXIF,
  thumbnails, cover image, served only through permission-checked view
- Search across title, description, ingredients, tags; ingredient and tag
  filters; "mine" and favourites views
- Admin can delete all recipes of a deactivated user
- Acceptance tests: private recipes unreachable for others and admins
  in list, search, tags, favourites, detail, edit, delete and image URLs

Co-Authored-By: Claude Opus 5.5 <[email protected]>

core/urls.py

@@ -5,6 +5,5 @@ from . import views
 app_name = "core"
 
 urlpatterns = [
-    path("", views.home, name="home"),
     path("healthz", views.healthz, name="healthz"),
 ]

core/views.py

@@ -6,10 +6,6 @@ from django.views.decorators.cache import never_cache
 from django.views.decorators.http import require_GET
 
 
-def home(request):
-    return render(request, "core/home.html")
-
-
 @login_not_required
 @never_cache
 @require_GET