Implement hard day exclusions for workers and add corresponding tests

rota/workers.py

@@ -145,6 +145,7 @@ class Worker(BaseModel):
     max_shifts_per_week_by_shift_name: dict[str, int] = {}  # e.g. {"night": 2, "a": 3}
     forced_assignments: List[tuple[int, str, str]] = []  # (week, day, shift_name)
     forced_assignments_by_date: List[tuple[datetime.date, str]] = []  # (date, shift_name)
+    max_days_worked_per_week: int | None= None # Default: no limit, can be set to a specific number
 
 
     assign_as_block_preferences: dict[str, float] = {}  # shift_name -> weight (positive = prefer block)
@@ -442,8 +443,6 @@ class Worker(BaseModel):
         days: List of days that must be grouped together.
         weeks: Optional list of weeks this dependency applies to. If None, applies to all weeks.
         """
-        if not hasattr(self, "hard_day_dependencies"):
-            self.hard_day_dependencies = []
         self.hard_day_dependencies.append(HardDayDependency(days=days, weeks=weeks, start_date=start_date, end_date=end_date))
 
     def add_hard_day_exclusion(self, days: set[str], weeks: Optional[List[int]] = None, start_date: Optional[datetime.date] = None, end_date: Optional[datetime.date] = None):
@@ -452,8 +451,6 @@ class Worker(BaseModel):
         days: List of days that must be excluded together.
         weeks: Optional list of weeks this exclusion applies to. If None, applies to all weeks.
         """
-        if not hasattr(self, "hard_day_exclusions"):
-            self.hard_day_exclusions = []
         self.hard_day_exclusions.append(HardDayExclusion(days=days, weeks=weeks, start_date=start_date, end_date=end_date))
 
     def add_force_assign_with(self, shift: str, with_shifts: list[str] | str):