Employees Shifts and public holidays

This module extends the shift planning functionality so that Odoo can recognise when a planned shift falls on a public holiday for the employee concerned.

• It adds a check on shift planning lines (hr.shift.planning.line) that looks at the shift's start date and the employee's address.
• Using the public holiday data from the calendar.public.holiday model, it determines whether that date is a public holiday for the employee's location.
• The check only runs when both a start date and an employee are present on the line; otherwise it simply returns no holiday.

Because the module contains no menus, views, or data files, it does not add new screens or buttons. Its effect is behind the scenes: other parts of the shift planning flow can use this holiday detection to avoid scheduling work on public holidays. The module depends on the public holiday calendar and the employee shift planning features, and it touches the hr.shift.planning.line model together with calendar.public.holiday. No automatic emails, scheduled jobs, or extra business rules beyond this holiday check are visible in the code.