feat(create-client): auto-link family member after client creation

- After creating a client from 'Create as Client' button, automatically
  call PUT /clients/{parentId}/familymembers/{memberId} with the new
  linkedClientId to link the family member record
- Show snackbar feedback on success or failure of the auto-link
- nomination-apply now also passes familyMemberId and parentClientId
  in prefill state so auto-link works from the nomination page too

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/app/election/components/nomination-apply/nomination-apply.component.ts

@@ -135,7 +135,9 @@ export class NominationApplyComponent implements OnInit {
       mobileNo: member.mobileNumber || '',
       dateOfBirth: member.dateOfBirth || null,
       panNumber: member.panNumber || '',
-      aadhaarNumber: member.aadhaarNumber || ''
+      aadhaarNumber: member.aadhaarNumber || '',
+      familyMemberId: member.id,
+      parentClientId: this.selectedMemberId
     };
     this.router.navigate(
       [