feat(cashier): denomination overdraft validation, exchange detail fix, cash exchange in reports

- Savings/Current/FD/RD withdrawal forms: card-style overdraft warning when
  requested denomination count exceeds cashier stock; submit blocked on overdraft
- Cash History detail view: show both RECEIVED and GIVEN denomination breakdowns
  for Cash Exchange (previously only RECEIVED side was displayed)
- Closing Cash Report: add Cash Exchanges section (denomination-wise received/given/net)
- Excess Transaction Report: include cash exchanges >= threshold with Type badge
  (Exchange/Txn) and ID Proof column for RBI/AML compliance
- cashier-shared.scss: etr-badge and closing-exchange-head styles
- Cash Exchange entry: overdraft warning redesigned to cx-overdraft-card BEM layout

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

src/app/cashier/cash-history/cash-history.component.scss

@@ -312,6 +312,38 @@
   border-color: #fcd34d;
 }
 
+// Cash exchange direction labels
+.cx-dir-label {
+  display: flex;
+  align-items: center;
+  gap: 6px;
+  margin: 8px 20px 4px;
+  padding: 6px 10px;
+  border-radius: 6px;
+  font-size: 11px;
+  font-weight: 700;
+  text-transform: uppercase;
+  letter-spacing: 0.06em;
+
+  mat-icon {
+    font-size: 14px;
+    height: 14px;
+    width: 14px;
+  }
+
+  &--received {
+    background: #eff6ff;
+    color: #1d4ed8;
+    border: 1px solid #bfdbfe;
+  }
+
+  &--given {
+    background: #fef3c7;
+    color: #92400e;
+    border: 1px solid #fcd34d;
+  }
+}
+
 .pg-btn--danger {
   background: linear-gradient(135deg, #ef4444, #b91c1c);
   color: #fff;