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/components/DiscountTab.tsx

@@ -11,6 +11,7 @@ import ConfirmDialog from './ui/ConfirmDialog';
 import SearchableSelect from './ui/SearchableSelect';
 import PriceInput from './ui/PriceInput';
 import PersianDateInput from './ui/PersianDateInput';
+import { digitsOnly } from '../lib/utils';
 
 const TYPE_LABELS: Record<DiscountRuleType, string> = {
   patient_tag:      'تگ بیمار',
@@ -239,12 +240,12 @@ function RuleModal({ initial, onClose, onSaved }: { initial: DiscountRule | null
           <div>
             <label style={labelStyle()}>{f.discount_type === 'percent' ? 'درصد تخفیف (۰ تا ۱۰۰)' : 'مبلغ تخفیف (تومان)'}</label>
             {f.discount_type === 'percent'
-              ? <input className="cp-input" style={{ width: '100%' }} type="number" inputMode="numeric" min={0} max={100} value={f.value} onChange={(e) => set('value', Number(e.target.value) || 0)} />
+              ? <input className="cp-input" style={{ width: '100%' }} type="text" inputMode="numeric" dir="ltr" value={f.value} onChange={(e) => set('value', Number(digitsOnly(e.target.value, 3)) || 0)} />
               : <PriceInput className="cp-input" style={{ width: '100%' }} value={f.value} onChange={(v) => set('value', v)} />}
           </div>
           <div>
             <label style={labelStyle()}>اولویت (بزرگ‌تر = مهم‌تر)</label>
-            <input className="cp-input" type="number" inputMode="numeric" min={0} value={f.priority} onChange={(e) => set('priority', Number(e.target.value) || 0)} />
+            <input className="cp-input" type="text" inputMode="numeric" dir="ltr" value={f.priority} onChange={(e) => set('priority', Number(digitsOnly(e.target.value)) || 0)} />
           </div>
         </div>
 
@@ -294,7 +295,7 @@ function RuleModal({ initial, onClose, onSaved }: { initial: DiscountRule | null
         {f.type === 'visit_count' && (
           <div>
             <label style={labelStyle()}>حداقل تعداد مراجعه</label>
-            <input className="cp-input" type="number" inputMode="numeric" min={1} value={f.min_visit_count} onChange={(e) => set('min_visit_count', Number(e.target.value) || 0)} />
+            <input className="cp-input" type="text" inputMode="numeric" dir="ltr" value={f.min_visit_count} onChange={(e) => set('min_visit_count', Number(digitsOnly(e.target.value)) || 0)} />
           </div>
         )}
         {f.type === 'occasion' && (