For chiefs of staff: Normalize holiday flags for marketing ops

Chiefs of staff in product and engineering face broken schedules when holiday APIs fail. Set fallback 'Unknown' so ops and engineers get consistent holiday flags and downstream jobs continue.

Overview

Holiday API gaps can misalign campaign sends and release windows, putting marketing launches and engineering rollouts at risk. Normalizing empty holiday responses to "Unknown" provides ops and engineering with a reliable flag so scheduling and downstream automations keep running and manual firefighting is reduced.

Notable Features

Detect missing holiday provider responses
Set fallback 'Unknown' holiday flag
Push consistent flags to schedulers