feat(phone-input): integrate phone number input component and validation

- Added `libphonenumber-js` dependency for improved phone number handling.
- Refactored `CreateAdmin` form to utilize a new `PhoneNumberInput` component with validation rules.
- Updated `useCreateAdminPresenter` to normalize phone number input before submission.
- Enhanced error messages for phone validation in `Texts` constant.
- Modified `User` schema to validate phone numbers using E.164 format.

src/components/FormElements/PhoneNumberInput/phone-field-rules.ts

@@ -0,0 +1,41 @@
+import { FormErrorMessages } from "@/constants/Texts";
+import { isValidE164Phone, normalizeToE164 } from "@/lib/phone/e164";
+import type { CountryCode } from "libphonenumber-js";
+
+type PhoneRulesOptions = {
+  required?: boolean;
+  defaultCountry?: CountryCode;
+};
+
+/** React Hook Form rules for an E.164 phone field. */
+export function createPhoneFieldRules(options: PhoneRulesOptions = {}) {
+  const { required = false, defaultCountry } = options;
+
+  return {
+    validate: (value: string | undefined) => {
+      const trimmed = value?.trim() ?? "";
+      if (!trimmed) {
+        return required ? FormErrorMessages.required : true;
+      }
+      if (!isValidE164Phone(trimmed)) {
+        return FormErrorMessages.invalidPhone;
+      }
+      return true;
+    },
+    setValueAs: (value: string | undefined) => {
+      const trimmed = value?.trim() ?? "";
+      if (!trimmed) return "";
+      return normalizeToE164(trimmed, defaultCountry) ?? trimmed;
+    },
+  };
+}
+
+/** Normalize before API submit (defensive). */
+export function normalizePhoneFieldValue(
+  value: string | undefined,
+  defaultCountry?: CountryCode,
+): string | undefined {
+  const trimmed = value?.trim();
+  if (!trimmed) return undefined;
+  return normalizeToE164(trimmed, defaultCountry) ?? undefined;
+}