Add phase 4: AI cleanup and photo/text import via OpenAI

- recipes/ai.py: Chat Completions with strict JSON schema (Structured
  Outputs), Pydantic re-validation, plausibility clamping, prompt treats
  input as data only
- "Mit KI aufbereiten" on create/edit form returns an editable draft
- Import page: photo/screenshot (vision, downscaled JPEG, not stored) and
  pasted text; drafts pre-fill the recipe form with a preview
- Clear UI messages for timeout, rate limit, quota, auth, model and
  connection errors; without OPENAI_API_KEY AI features show a notice
- Optional per-user and global daily AI limits (default unlimited)
- Tests for response parsing, schema strictness, error mapping, views

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

recipes/urls.py

@@ -1,12 +1,15 @@
 from django.urls import path
 
-from . import views
+from . import import_views, views
 
 app_name = "recipes"
 
 urlpatterns = [
     path("", views.recipe_list, name="list"),
     path("rezepte/neu/", views.recipe_create, name="create"),
+    path("rezepte/import/", import_views.import_start, name="import"),
+    path("rezepte/import/foto/", import_views.import_photo, name="import_photo"),
+    path("rezepte/import/text/", import_views.import_text, name="import_text"),
     path("rezepte/<int:pk>/", views.recipe_detail, name="detail"),
     path("rezepte/<int:pk>/bearbeiten/", views.recipe_edit, name="edit"),
     path("rezepte/<int:pk>/loeschen/", views.recipe_delete, name="delete"),