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/RepresentationsPage.tsx

@@ -18,6 +18,7 @@ import Pagination from '../components/ui/Pagination';
 import ConfirmDialog from '../components/ui/ConfirmDialog';
 import Modal from '../components/ui/Modal';
 import SearchableSelect from '../components/ui/SearchableSelect';
+import { numericField } from '../lib/forms';
 
 const schema = z.object({
   full_name:          z.string().min(2, 'نام الزامی است'),
@@ -248,7 +249,7 @@ export default function RepresentationsPage() {
           </div>
           <div className="form-row" style={{ marginTop: 12 }}>
             <label>درصد کمیسیون</label>
-            <input {...register('commission_percent')} type="number" min="0" max="100" placeholder="10" dir="ltr"
+            <input {...numericField(register('commission_percent'), 3)} placeholder="10" dir="ltr"
               className="input" />
             {errors.commission_percent && <p className="err-text">{errors.commission_percent.message}</p>}
           </div>