feat: recipe CRUD endpoints with canonical ingredient validation

POST/PATCH validate every ingredient_id against the ingredient table
and return 422 with the missing list when refs don't resolve. Replaces
the prior recipes.py stub. Public read routes + admin write routes.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

backend/app/main.py

@@ -29,15 +29,17 @@ def health_check_db(db: Session = Depends(get_db)):
         return {"status": "error", "database": "disconnected", "error": str(e)}
 
 
-from app.api import profile, recipes, meals, shopping_list, pantry, admin, auth
+from app.api import profile, meals, shopping_list, pantry, admin, auth
 from app.api import ingredients as ingredients_api
+from app.api import recipes as recipes_api
 
 app.include_router(auth.router, prefix="/api/auth", tags=["auth"])
 app.include_router(profile.router, prefix="/api/profile", tags=["profile"])
-app.include_router(recipes.router, prefix="/api/recipes", tags=["recipes"])
 app.include_router(meals.router, prefix="/api/meals", tags=["meals"])
 app.include_router(shopping_list.router, prefix="/api/shopping-list", tags=["shopping-list"])
 app.include_router(pantry.router, prefix="/api/pantry", tags=["pantry"])
 app.include_router(admin.router, prefix="/api/admin", tags=["admin"])
 app.include_router(ingredients_api.public_router)
 app.include_router(ingredients_api.admin_router)
+app.include_router(recipes_api.public_router)
+app.include_router(recipes_api.admin_router)