feat(admin): normalize Persian/Arabic digits in every numeric field

Users typing on a Persian keyboard produced two distinct failures. Fields with
type="number" silently returned an empty string — the browser rejects Persian
digits, so the value was lost and saved as empty or zero. Text fields passed the
Persian characters straight through to the database, where a mobile stored as
۰۹۱۲… never matches 09… again. The secretary form hit the second case with no
validation at all.

Frontend:
- Adds digitsOnly() and the national-code schemas to lib/utils, plus lib/forms
  with numericField()/latinDigitsField() wrappers for React Hook Form fields.
- Converts every type="number" input to type="text" inputMode="numeric" with
  digit normalization; none remain. Fields that legitimately carry non-digits
  (sheba, landline) only get the digits translated, keeping IR and separators.
- Points the patient national-code and mobile schemas at the shared normalizing
  schemas, which accept Persian input instead of rejecting it.
- Drops two duplicate local digit converters in favour of the shared helper.

Backend:
- Adds NumericFieldNormalizerSubscriber, translating digits in whitelisted
  numeric keys of JSON request bodies under /api/v1/ before controllers run, so
  nobat724_front and clinic-pro-tauri are covered too. Translation only — no
  characters are stripped, non-string values and other keys are untouched.

Three component tests asserted on role="spinbutton" and numeric input values;
both are properties of type="number", so they were updated to match the new
text inputs.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

assets/admin/pages/AppointmentsPage.tsx

@@ -9,7 +9,7 @@ import { toast } from 'sonner';
 import { api } from '../lib/api';
 import type { PaginatedResponse, ApiResponse } from '../lib/api';
 import type { Appointment } from '../types';
-import { formatDate, toGregorianDate, formatTime, toEnglishDigits, sanitizeMobileInput, rialToToman, tomanToRial } from '../lib/utils';
+import { formatDate, toGregorianDate, formatTime, digitsOnly, sanitizeMobileInput, rialToToman, tomanToRial } from '../lib/utils';
 import PriceInput from '../components/ui/PriceInput';
 import { useAuthStore } from '../stores/authStore';
 import Pagination from '../components/ui/Pagination';
@@ -280,7 +280,7 @@ export function NewAppointmentModal({
                 lang="en"
                 maxLength={10}
                 value={nationalCode}
-                onChange={e => setNationalCode(toEnglishDigits(e.target.value).replace(/\D/g, '').slice(0, 10))}
+                onChange={e => setNationalCode(digitsOnly(e.target.value, 10))}
                 placeholder="کد ملی ۱۰ رقمی"
                 style={{ ...inputSx, direction: 'ltr' }}
               />