* feat(api): collapse Slack, portal, and jobs onto Fargate (PLAT-216)
Move HTTP and scheduled work onto one always-on Flask task so after-hours
loses Lambda cold start without changing the Cognito or roster contracts.
* fix(portal-api): keep CORS headers on unexpected 500s
Portal SPA error handling needs Access-Control-Allow-Origin even when
DynamoDB or other internals fail, otherwise the browser hides the 500.
* fix(api): retarget holidays per account and ship App Home changelog (PLAT-216)
* fix(iam): list ECS tasks and fail closed on non-prod Paychex (PLAT-216)
* fix(portal-api): serve portal JSON with an explicit JSON content type
