Update configured shift flag every Friday at 4pm

Your shift marker can stay stale, causing on-call handoffs to use the wrong state. It updates the marker every Friday at 4pm so managers and scripts see correct state before weekend ops.

Overview

Eliminate weekend handoff errors by making the canonical shift state authoritative and punctual. Automatically set the shared shift marker every Friday at 4pm so on-call managers and automation act on the correct context ahead of weekend maintenance.