fix(cashier,chequebook): surface real backend errors; skip redundant balance check on token disbursement

Cashier token-based withdrawal disbursement was re-running the balance/min-balance
checks against the already-approved amount, which always failed since the manager
approval had already deducted the balance — the check now skips for that case
(clerk-created requests still get the full validation).

Cheque book request submission now shows the actual backend error message
(e.g. insufficient-balance rejections) instead of a generic fallback string.

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

src/app/chequebook/cheque-books/cheque-books.component.ts

@@ -281,9 +281,13 @@ export class ChequeBooksComponent implements OnInit {
         this.notify('Submitted for approval — see Approvals > Cheque Book Requests');
         this.loadBooks();
       },
-      error: () => {
+      error: (err: any) => {
         this.busy = false;
-        this.notify('Request failed — check the account is active and the cheque-book facility is enabled', true);
+        const msg =
+          err?.error?.errors?.[0]?.defaultUserMessage ||
+          err?.error?.developerMessage ||
+          'Request failed — check the account is active and the cheque-book facility is enabled';
+        this.notify(msg, true);
       }
     });
   }