fix(playbook): seed tuple unpack + text[] → jsonb migration

- playbook_seed_service.py: list_playbooks 回傳 tuple[list, int]，
  缺少解包導致 'list' has no attribute 'source'
- fix_playbooks_array_to_jsonb.sql: source_incident_ids/tags text[] → jsonb
  （已手動套用 prod DB）

2026-04-15 ogt + Claude Sonnet 4.6（亞太）

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

apps/api/src/services/playbook_seed_service.py

@@ -43,7 +43,7 @@ async def seed_playbooks_from_rules() -> None:
         repo = get_playbook_repository()
 
         # 取得現有 playbook source_ids，避免重複建立
-        existing = await repo.list_playbooks(status=PlaybookStatus.APPROVED, limit=500)
+        existing, _ = await repo.list_playbooks(status=PlaybookStatus.APPROVED, limit=500)
         existing_sources = {p.source for p in existing if p.source}
 
         seeded = 0