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/ClinicsPage.tsx

@@ -21,6 +21,7 @@ import Portal from '../components/ui/Portal';
 import { formatDate, formatNumber, iranMobileSchema } from '../lib/utils';
 import Pagination from '../components/ui/Pagination';
 import ConfirmDialog from '../components/ui/ConfirmDialog';
+import { latinDigitsField } from '../lib/forms';
 
 const HUES_LIST = [256, 205, 162, 295, 272];
 
@@ -275,7 +276,7 @@ export default function ClinicsPage() {
                   <label style={{ fontSize: 13, fontWeight: 600, marginBottom: 6, display: 'block' }}>
                     تلفن (اختیاری)
                   </label>
-                  <input className="input" placeholder="مثال: 021-12345678" dir="ltr" {...addForm.register('telephone')} />
+                  <input className="input" placeholder="مثال: 021-12345678" {...latinDigitsField(addForm.register('telephone'))} />
                 </div>
               </div>
               <div className="modal-foot">