Configurable automatic nightlight schedule

[heymaikol]

Problem

Omarchy ships hyprsunset for the manual nightlight toggle (SUPER+CTRL+N, omarchy toggle nightlight), but the automatic time-based behaviour hyprsunset supports natively is opt-in only through manual config editing.

Today, turning the screen warm at sundown and back to identity in the morning requires the user to:

1. Add exec-once = uwsm-app -- hyprsunset to ~/.config/hypr/autostart.lua (or .conf pre-migration)
2. Append a second profile { time = ...; temperature = ... } block to ~/.config/hypr/hyprsunset.conf

The current default config/hypr/hyprsunset.conf documents this in comments (added in #2446 and #3082), but there's no one-step or interactive way to enable, change, or disable it. Discoverability is poor and the schedule resets on a refresh.

Proposed UX

A managed, opt-in schedule with persistent settings:

• Off by default (no behaviour change for users who don't opt in)
• A single discoverable entry under Trigger → Toggle that opens a UI showing current status, intensity (K), start time, and end time
• The UI lets the user enable/disable the schedule and change each value
• Settings persist across reboots/refreshes and survive omarchy refresh hyprsunset cleanly (managed state stored outside the config file)