improvement: treatment exits contoll adde to appoinment remove action.

frontend/messages/en.json

@@ -582,6 +582,7 @@
     "confirmRemove": "Remove this appointment?",
     "successRemoved": "Appointment removed.",
     "errorDelete": "Could not delete appointment.",
+    "deleteBlockedHint": "This appointment cannot be deleted because a treatment is linked to it.",
     "errorLoadSchedule": "Failed to load schedule.",
     "successPatientSaved": "Patient {firstName} {lastName} was saved.",
     "searchPlaceholder": "Search existing patients",
@@ -1013,6 +1014,7 @@
     "CONFLICT": "This action conflicts with existing data.",
     "CONFLICT_FUTURE_APPOINTMENTS": "You cannot stop participating in treatments while you have future appointments. Reassign or cancel them first.",
     "APPOINTMENT_PATIENT_LOCKED": "Cannot change the patient while a treatment is linked to this appointment.",
+    "APPOINTMENT_HAS_TREATMENT": "This appointment cannot be deleted because a treatment is linked to it.",
     "BAD_REQUEST": "The request could not be processed.",
     "INTERNAL_ERROR": "Something went wrong on our end. Please try again later."
   }