Add CRM order queue: live sync, view modal, receipt tabs, delete

Wires the CRM (exoCRM GetOrders) into the dashboard as a locally
persisted order queue instead of the previous static mockup:

- CrmClient Protocol + ExoCrmClient/StubCrmClient for the CRM's
  signed JSON-RPC API
- Order model + migration, synced from CRM on each queue view;
  soft-deleted orders stay hidden across re-syncs
- GET/DELETE /api/v1/orders with "no receipt"/"receipt issued" tabs
  (the latter is empty until Checkbox fiscalization lands)
- Dashboard: real order list, item-detail modal, tab switcher,
  one-click delete

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

frontend/src/pages/DashboardPage.css

@@ -85,6 +85,32 @@
   cursor: not-allowed;
 }
 
+.orders-tabs {
+  display: flex;
+  gap: 8px;
+}
+
+.orders-tab {
+  border: 1px solid var(--color-border);
+  background: var(--color-surface);
+  color: var(--color-text-muted);
+  border-radius: 999px;
+  padding: 6px 16px;
+  font-size: 13px;
+  font-weight: 600;
+  cursor: pointer;
+}
+
+.orders-tab:hover {
+  color: var(--color-text);
+}
+
+.orders-tab--active {
+  background: var(--color-primary);
+  border-color: var(--color-primary);
+  color: #fff;
+}
+
 .orders-filterbar {
   display: flex;
   align-items: center;
@@ -198,6 +224,11 @@
   color: #166534;
 }
 
+.orders-status--approved {
+  background: #dcfce7;
+  color: #166534;
+}
+
 @media (prefers-color-scheme: dark) {
   .orders-status--processing {
     background: rgba(217, 119, 6, 0.18);
@@ -213,6 +244,50 @@
     background: rgba(22, 163, 74, 0.18);
     color: #86efac;
   }
+
+  .orders-status--approved {
+    background: rgba(22, 163, 74, 0.18);
+    color: #86efac;
+  }
+}
+
+.orders-actions-cell {
+  display: flex;
+  gap: 8px;
+}
+
+.orders-view-btn {
+  border: 1px solid var(--color-border);
+  background: var(--color-surface);
+  color: var(--color-text);
+  border-radius: 6px;
+  padding: 6px 12px;
+  font-size: 13px;
+  cursor: pointer;
+}
+
+.orders-view-btn:hover {
+  border-color: var(--color-primary);
+  color: var(--color-primary);
+}
+
+.orders-delete-btn {
+  border: 1px solid var(--color-border);
+  background: var(--color-surface);
+  color: #b91c1c;
+  border-radius: 6px;
+  padding: 6px 12px;
+  font-size: 13px;
+  cursor: pointer;
+}
+
+.orders-delete-btn:hover:not(:disabled) {
+  border-color: #b91c1c;
+}
+
+.orders-delete-btn:disabled {
+  opacity: 0.5;
+  cursor: not-allowed;
 }
 
 .orders-receipt-btn {