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/RepresentationSettlementPage.tsx

@@ -6,6 +6,7 @@ import type { ApiResponse } from '../lib/api';
 import { formatRial, formatDate, tomanToRial } from '../lib/utils';
 import Pagination from '../components/ui/Pagination';
 import SearchableSelect from '../components/ui/SearchableSelect';
+import { digitsOnly } from '../lib/utils';
 
 interface WalletBalance { balance_rials: number }
 interface RepSummary { income: { settlable_rials: number; settled_rials: number; pending_rials: number } }
@@ -127,8 +128,8 @@ export default function RepresentationSettlementPage() {
         ) : (
           <div style={{ display: 'flex', alignItems: 'center', gap: 8, flexWrap: 'wrap' }}>
             <input
-              type="number" min={0} dir="ltr" value={amount} placeholder="مبلغ به تومان"
-              onChange={(e) => setAmount(e.target.value)}
+              type="text" inputMode="numeric" dir="ltr" value={amount} placeholder="مبلغ به تومان"
+              onChange={(e) => setAmount(digitsOnly(e.target.value))}
               style={{ width: 200, height: 38, padding: '0 12px', borderRadius: 'var(--r-sm)', border: '1px solid var(--border)', background: 'var(--surface)', color: 'var(--text)', fontSize: 13.5, boxSizing: 'border-box' }}
             />
             <div style={{ width: 320 }}>