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/AppointmentCreatePage.tsx

@@ -14,6 +14,7 @@ import { WalletChargeLink } from '../components/AppointmentActions';
 import { useDoctorBookingServices } from '../hooks/useDoctorBookingServices';
 import ServiceSlotPicker from '../components/appointments/ServiceSlotPicker';
 import { tehranWallClockToUnix, rialToToman, tomanToRial } from '../lib/utils';
+import { digitsOnly } from '../lib/utils';
 
 /**
  * افزودن نوبت — صفحهٔ کامل (بازسازی `CreateTurn.jsx` طرح tauri). از همان endpointهای
@@ -434,7 +435,7 @@ export default function AppointmentCreatePage() {
             <div>
               <label style={label}>زمان پیش فرض (دقیقه)</label>
               <div className="field" style={{ marginTop: 6, height: 44 }}>
-                <input aria-label="زمان پیش فرض" type="number" min={5} value={duration} onChange={e => setDuration(Math.max(5, Number(e.target.value) || 0))} dir="ltr" />
+                <input aria-label="زمان پیش فرض" type="text" inputMode="numeric" value={duration} onChange={e => setDuration(Math.max(5, Number(digitsOnly(e.target.value)) || 0))} dir="ltr" />
               </div>
             </div>
             <div>