修復三個串聯 bug,讓 Playbook seed 能正常執行: 1. PlaybookSource 新增 YAML_RULE enum(alert_rules.yaml 匯入專用) 2. playbook_seed_service: source=YAML_RULE,dedup 改用 raw SQL by name, 不再呼叫 list_playbooks(舊格式 repair_steps 會 validation error) 3. playbook_repository._orm_to_pydantic: 舊格式 repair_steps 補齊 step_number/action_type 必填欄位(向下相容) 4. flywheel_stats_service: embedding IS NULL 改用 raw SQL, 修復 KnowledgeEntryRecord ORM 無 embedding 屬性的 AttributeError Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>