refactor: remove routine_role, recommended_frequency, evidence_level, cumulative_with

Drop fields identified as redundant or low-value from the Product model,
API schemas, frontend types, and forms. Raise effect_profile threshold in
to_llm_context() from >0 to >=2 to suppress noise values. Remove sku/barcode
from LLM context output (kept on model for catalog use).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/tests/conftest.py

@@ -53,7 +53,6 @@ def product_data():
         "name": "CeraVe Moisturising Cream",
         "brand": "CeraVe",
         "category": "moisturizer",
-        "routine_role": "seal",
         "recommended_time": "both",
         "leave_on": True,
     }