Integrate #3/#5/#6 (week-start, time-format, hour-lines) into the agenda
range branch. SettingsViewModel folds all five view prefs into one combine;
WidgetData keeps the range-based window and adds the resolved is24Hour.
Also, in the same Appearance section:
- regroup the rows into four titled-by-spacing groups (theme & colour /
calendar layout / timeline display / agenda) instead of one long card.
- add an explanatory description line under the title of each agenda-range
picker (PickerDescription).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>