Holiday day-shifts (08:00-17:00 ET) with N slots and 1.5x pay. A new
afterhours-holiday-router Lambda, fired by per-holiday EventBridge Scheduler
one-offs, repoints IVR 800 (key-0 + no-input/timeout) to holiday queue 802 and
sets 802's membership to the day's assignees (ext 100 fallback when unfilled),
reverting at 17:00. Pickups after a shift starts go through an admin Approve/Deny
flow for both regular and holiday shifts. Pay (weekly post + /oncall pay) shows
holiday rates distinctly.
Adds HOLIDAY and PICKUP_REQUEST DynamoDB record types, scheduler IAM scoped to
holiday-* schedules with conditioned PassRole, and the holiday-router function
with a 60-day log group and error alarm.
