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/InsuranceModal.tsx

@@ -3,6 +3,7 @@ import Modal from './ui/Modal';
 import SearchableSelect from './ui/SearchableSelect';
 import PersianDateInput from './ui/PersianDateInput';
 import { isoToUnix, rialToToman, tomanToRial, unixToIso } from '../lib/utils';
+import { digitsOnly } from '../lib/utils';
 
 export interface InsuranceOption {
   insurance_id: number;
@@ -161,15 +162,15 @@ export default function InsuranceModal({ open, editContract, options, kind, onCl
         <div style={{ display: 'grid', gridTemplateColumns: '1fr 1fr 1fr', gap: 12 }}>
           <div style={field}>
             <label style={label}>درصد پوشش</label>
-            <input type="number" min={0} max={100} dir="ltr" className="input" value={form.coverage} onChange={(e) => set({ coverage: e.target.value })} />
+            <input type="text" inputMode="numeric" dir="ltr" className="input" value={form.coverage} onChange={(e) => set({ coverage: digitsOnly(e.target.value, 3) })} />
           </div>
           <div style={field}>
             <label style={label}>فرانشیز (تومان)</label>
-            <input type="number" min={0} dir="ltr" className="input" value={form.franchise} onChange={(e) => set({ franchise: e.target.value })} />
+            <input type="text" inputMode="numeric" dir="ltr" className="input" value={form.franchise} onChange={(e) => set({ franchise: digitsOnly(e.target.value) })} />
           </div>
           <div style={field}>
             <label style={label}>سقف تعهد (تومان)</label>
-            <input type="number" min={0} dir="ltr" className="input" placeholder="بی‌نهایت" value={form.ceiling} onChange={(e) => set({ ceiling: e.target.value })} />
+            <input type="text" inputMode="numeric" dir="ltr" className="input" placeholder="بی‌نهایت" value={form.ceiling} onChange={(e) => set({ ceiling: digitsOnly(e.target.value) })} />
           </div>
         </div>
       </div>