Timeline date picker ignores "Start of week: Monday" setting

[tomlabirt]

Description:

The Timeline view's date range picker does not respect the configured start-of-week setting.

Steps to reproduce:

Open Settings.

Set "Start of week" to "Monday".

Navigate to the Timeline view.

Open the date range picker.

Expected behavior:
The calendar should display Monday as the first day of the week, consistent with the global setting.

Actual behavior:
The calendar always starts the week on Sunday, regardless of the configured setting.

Environment:

ActivityWatch: v0.14.0

OS: Windows

Additional notes:
The date picker should use the same start-of-week preference as the rest of the application.