Configurable Start Day of the Week

[eran-rom]

I proposes adding an option to configure which day of the week is treated as the first day, this will be true for everything week-related, specifically useful for Calendar View, Due Dates and Scheduled Dates.

This will make TaskNotes much more relevant and intuitive for users worldwide by correctly aligning with their local or professional calendar standards, ensuring that weekly task planning, time tracking, and visualization accurately reflect the user's actual work or personal schedule.