CodeBench: vahvista CRITICAL-sääntö — ei ylimääräisiä kenttiä

qwen3:14b lisäsi created_at spekin ulkopuolelta ja käytti
server_default=datetime.now (virheellinen). Nostettu CRITICAL-tasolle.

kipina-codebench/prompts/code.md

@@ -32,8 +32,8 @@ RULES:
 - Tests: unique descriptive data per test, NOT generic "test_title" strings
 - Tests: PUT/update test data MUST include ALL required (non-nullable) fields, not just the field being updated
 - Do NOT add filter/search endpoints — only standard CRUD (create, list, get, update, delete)
-- Do NOT add fields beyond what the JSON spec defines — no extra created_at, updated_at, or other fields not in spec
-- If the spec includes timestamp fields: use server_default=func.now() (import func from sqlalchemy) and make them Optional in Create schema
+- CRITICAL: Use ONLY the fields listed in the JSON spec. NEVER add created_at, updated_at, or any field not in the spec
+- If the spec happens to include timestamp fields: use server_default=func.now() (from sqlalchemy import func) and make them Optional in Create schema
 - Absolute imports only (from models import ..., from schemas import ...)
 - NO markdown fences inside file content — just raw code
 - Only test endpoints that exist in main.py — no extra tests