feat(timezone): implement Tehran timezone handling across the application

assets/admin/components/AppointmentActions.tsx

@@ -20,7 +20,7 @@ import { useNavigate } from "react-router-dom";
 import { toast } from "sonner";
 import type { ApiResponse } from "../lib/api";
 import { api } from "../lib/api";
-import { formatRial } from "../lib/utils";
+import { formatRial, tehranWallClockToUnix } from "../lib/utils";
 import type { Appointment } from "../types";
 import AppointmentStatusDropdown from "./ui/AppointmentStatusDropdown";
 import Modal from "./ui/Modal";
@@ -30,8 +30,7 @@ import PriceInput from "./ui/PriceInput";
 /** Row actions for the appointments table (Figma عملیات menu). */
 type ModalKind = null | "info" | "move" | "transfer" | "replace";
 
-const toEpoch = (isoDate: string, time: string) =>
-    Math.floor(new Date(`${isoDate}T${time || "00:00"}`).getTime() / 1000);
+const toEpoch = (isoDate: string, time: string) => tehranWallClockToUnix(isoDate, time);
 
 /**
  * Resolve the patient-record uuid behind an appointment via the patient list