fix(clients): stale signature bug, monthly turnover/annual income fields, senior citizen/PWD classification

- Fix signature-document reads picking the oldest upload instead of the latest across 7 call
  sites (CKYC tab, view/delete-signature dialogs, edit-wizard preview, cashier transaction entry,
  signatory service, record-master) by sorting on document id instead of an unsorted find().
- Add Monthly Turnover and Annual Income fields alongside the renamed Yearly Turnover field.
- Add Senior Citizen (auto-detected from DOB) and Person with Disability classification, with a
  required disability-certificate upload gate before client creation can proceed.
- Add Graduate and Diploma as distinct Education Levels, with diploma-specific degree options.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/app/clearing-network/signatory.service.ts

@@ -66,9 +66,12 @@ export class SignatoryService {
   fetchClientSignature(clientId: number | string): Observable<string | null> {
     return this.http.get<any[]>(`/clients/${clientId}/documents`).pipe(
       switchMap((docs: any[]) => {
-        const sigDoc = (docs || []).find(
-          (d: any) => d.name === 'clientSignature' || d.name?.toLowerCase().includes('signature')
-        );
+        // Multiple 'clientSignature' documents can exist for clients who re-cropped/replaced
+        // their signature before uploads became single-slot, so pick the highest id (latest)
+        // rather than the first unordered match.
+        const sigDoc = (docs || [])
+          .filter((d: any) => d.name === 'clientSignature' || d.name?.toLowerCase().includes('signature'))
+          .sort((a: any, b: any) => b.id - a.id)[0];
         if (!sigDoc) {
           return of(null);
         }