feat(backend): recipe enrichment with side dishes & detailed instructions

- Add SideDish/SideDishIngredient schemas and recipe.side_dishes JSONB column
- Add recipe_enrichment.py service using Ollama LLM to:
  - Rewrite vague instructions with specific temps, quantities, timing, sauce breakdowns
  - Suggest 1-2 complementary side dishes with ingredients & prep notes
- Wire enrichment into recipe_ingestion.py discovery pipeline
- Add admin trigger endpoint /api/recipes/{id}/enrich for on-demand enrichment
- Migration 0014: Add side_dishes JSONB to recipe table
- Fix schemas/__init__.py imports: restore RecipeBase/Create/Read exports, add datetime/date for PydanticOptional compatibility
- Deployed to docker-willester and migrated to alembic 0014

backend/app/schemas/__init__.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+from datetime import date, datetime
 from decimal import Decimal
 from enum import Enum
 from typing import Any, Dict, List, Optional