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/ClinicServicesPage.tsx

@@ -21,6 +21,7 @@ import ServiceTariffModal from '../components/ServiceTariffModal';
 import ServiceInsuranceModal from '../components/ServiceInsuranceModal';
 import SearchableSelect from '../components/ui/SearchableSelect';
 import FeatureGate from '../components/ui/FeatureGate';
+import { numericField } from '../lib/forms';
 
 const sectionSchema = z.object({ name: z.string().min(1, 'نام بخش الزامی است') });
 const itemSchema = z.object({
@@ -526,7 +527,7 @@ function ClinicServicesPageInner() {
               <div>
                 <label className="field-label">زمان متوسط (دقیقه)</label>
                 <div className="field">
-                  <input type="number" min={0} {...itemForm.register('duration_minutes')} placeholder="مثلاً: ۵۰" />
+                  <input {...numericField(itemForm.register('duration_minutes'))} placeholder="مثلاً: 50" />
                 </div>
               </div>
               <label style={{ display: 'flex', alignItems: 'center', gap: 10, cursor: 'pointer', padding: '9px 0' }}>