Feature: Add a separate control for apply color filter (gray)

**Describe the enhancement or feature you'd like**

the filter is toggled with it's own schedule
set light mode as the disabled state of the color filter or give it a different time to undo color filer

**Describe alternatives you've considered**

**Additional context**
Add any other context or screenshots about the feature request here.

This feature is inspired from "Bed Time Modes" in Android 15

No files, tests, or entry points are named. Begin by tracing the existing theme schedule and color-filter handling, then define completion as an independently configurable color-filter control with its own schedule and clear disabled or light-mode behavior.

Written by the indexing model from the issue text.