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/clients/client-stepper/client-kyc-step/client-kyc-step.component.ts

@@ -845,7 +845,12 @@ export class ClientKycStepComponent implements OnInit, OnChanges, OnDestroy {
     if (!this.clientId) return;
     this.clientsService.getClientDocuments(this.clientId).subscribe({
       next: (documents: any[]) => {
-        const sigDoc = documents?.find((d: any) => d.name === 'clientSignature');
+        // 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 = documents
+          ?.filter((d: any) => d.name === 'clientSignature')
+          ?.sort((a: any, b: any) => b.id - a.id)?.[0];
         if (sigDoc?.id) {
           this.existingSignatureDocId = sigDoc.id.toString();
           this.clientsService.getClientSignatureImage(this.clientId, this.existingSignatureDocId).subscribe({