Created and activated the booking integrity ExecPlan, then implemented staff availability, overlap prevention, and duration validation with backend tests.

Added a staff availability model and migration, a booking validation service, and serializer enforcement.

backend/apps/salons/models.py

@@ -59,6 +59,34 @@ class StaffProfile(models.Model):
         return f"{self.user.email} - {self.salon.name}"
 
 
+class StaffAvailability(models.Model):
+    DAY_CHOICES = [
+        (0, "Monday"),
+        (1, "Tuesday"),
+        (2, "Wednesday"),
+        (3, "Thursday"),
+        (4, "Friday"),
+        (5, "Saturday"),
+        (6, "Sunday"),
+    ]
+
+    staff = models.ForeignKey(
+        StaffProfile,
+        on_delete=models.CASCADE,
+        related_name="availability",
+    )
+    day_of_week = models.PositiveSmallIntegerField(choices=DAY_CHOICES)
+    start_time = models.TimeField()
+    end_time = models.TimeField()
+    is_active = models.BooleanField(default=True)
+
+    class Meta:
+        ordering = ["staff_id", "day_of_week", "start_time"]
+
+    def __str__(self):
+        return f"{self.staff.user.email} {self.get_day_of_week_display()} {self.start_time}-{self.end_time}"
+
+
 class Review(models.Model):
     salon = models.ForeignKey(Salon, on_delete=models.CASCADE, related_name="reviews")
     customer = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, related_name="reviews")