Services Desk display hours

The fleet runs daily from 10:00 AM until 10:00 PM in America/Chicago,
including automatic daylight-saving changes. The local user timer
sol37-desk-screen-hours.timer reconciles the current time at both boundaries
and 30 seconds after the user service manager starts. Persistent catch-up
uses the current time rather than replaying a missed start overnight.

bin/sol37_desk_screen_hours.py starts the existing fleet service during the
day and invokes its ownership-aware --stop-displays command at night.
The fleet's quiet-hours.conf ExecCondition also blocks manual or automatic
service starts overnight. Existing fleet mode and target settings are retained.
The stop operation closes the dedicated Mac kiosk and clears recognized fleet
media from approved receivers; it does not power off unrelated television use.
Unavailable receivers are reported in the stopped ledger and are not physical
screen-off confirmation. The host must be running for scheduled operations.

Inspect with systemctl --user list-timers sol37-desk-screen-hours.timer
and python3 bin/sol37_desk_screen_fleet.py --status. The current stop results
are in ~/.local/state/sol37/services-desk-screen-fleet-stopped.json.