feat: add restart server action for vendor and tenant

Vendor: POST /api/vendor/tenants/{id}/restart (platform:admin scope)
Tenant: POST /api/tenant/server/restart (tenant:manage scope)

Both call TenantProvisioner.stop() then start() on the server + UI
containers. Restart button on vendor TenantDetailPage (Actions card)
and tenant TenantDashboardPage (Server card). Allowed in any status
including PROVISIONING.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

ui/src/api/tenant-hooks.ts

@@ -10,6 +10,14 @@ export function useTenantDashboard() {
   });
 }
 
+export function useRestartServer() {
+  const qc = useQueryClient();
+  return useMutation<void, Error, void>({
+    mutationFn: () => api.post('/tenant/server/restart'),
+    onSuccess: () => qc.invalidateQueries({ queryKey: ['tenant', 'dashboard'] }),
+  });
+}
+
 export function useTenantLicense() {
   return useQuery<TenantLicenseData>({
     queryKey: ['tenant', 'license'],

ui/src/api/vendor-hooks.ts

@@ -54,6 +54,14 @@ export function useDeleteTenant() {
   });
 }
 
+export function useRestartServer() {
+  const qc = useQueryClient();
+  return useMutation<void, Error, string>({
+    mutationFn: (id) => api.post(`/vendor/tenants/${id}/restart`),
+    onSuccess: (_, id) => qc.invalidateQueries({ queryKey: ['vendor', 'tenants', id] }),
+  });
+}
+
 export function useRenewLicense() {
   const qc = useQueryClient();
   return useMutation<LicenseResponse, Error, string>({

ui/src/pages/tenant/TenantDashboardPage.tsx

@@ -6,9 +6,10 @@ import {
   Card,
   KpiStrip,
   Spinner,
+  useToast,
 } from '@cameleer/design-system';
-import { ExternalLink, Key, Settings } from 'lucide-react';
-import { useTenantDashboard } from '../../api/tenant-hooks';
+import { ExternalLink, Key, RefreshCw, Settings } from 'lucide-react';
+import { useTenantDashboard, useRestartServer } from '../../api/tenant-hooks';
 import { ServerStatusBadge } from '../../components/ServerStatusBadge';
 import { UsageIndicator } from '../../components/UsageIndicator';
 import { tierColor } from '../../utils/tier';
@@ -26,7 +27,9 @@ function statusColor(status: string): 'success' | 'error' | 'warning' | 'auto' {
 
 export function TenantDashboardPage() {
   const navigate = useNavigate();
+  const { toast } = useToast();
   const { data, isLoading, isError } = useTenantDashboard();
+  const restartServer = useRestartServer();
 
   if (isLoading) {
     return (
@@ -96,6 +99,23 @@ export function TenantDashboardPage() {
                 <span className={styles.kvValueMono}>{data.serverEndpoint}</span>
               </div>
             )}
+            <div style={{ paddingTop: 8 }}>
+              <Button
+                variant="secondary"
+                onClick={async () => {
+                  try {
+                    await restartServer.mutateAsync();
+                    toast({ title: 'Server restarted', variant: 'success' });
+                  } catch (err) {
+                    toast({ title: 'Restart failed', description: String(err), variant: 'error' });
+                  }
+                }}
+                loading={restartServer.isPending}
+              >
+                <RefreshCw size={14} style={{ marginRight: 6 }} />
+                Restart Server
+              </Button>
+            </div>
           </div>
         </Card>
 

ui/src/pages/vendor/TenantDetailPage.tsx

@@ -16,6 +16,7 @@ import {
   useActivateTenant,
   useDeleteTenant,
   useRenewLicense,
+  useRestartServer,
 } from '../../api/vendor-hooks';
 import { ServerStatusBadge } from '../../components/ServerStatusBadge';
 import { tierColor } from '../../utils/tier';
@@ -67,6 +68,7 @@ export function TenantDetailPage() {
   const activateTenant = useActivateTenant();
   const deleteTenant = useDeleteTenant();
   const renewLicense = useRenewLicense();
+  const restartServer = useRestartServer();
 
   const [deleteOpen, setDeleteOpen] = useState(false);
 
@@ -105,6 +107,16 @@ export function TenantDetailPage() {
     }
   }
 
+  async function handleRestart() {
+    if (!id) return;
+    try {
+      await restartServer.mutateAsync(id);
+      toast({ title: 'Server restarted', variant: 'success' });
+    } catch (err) {
+      toast({ title: 'Restart failed', description: String(err), variant: 'error' });
+    }
+  }
+
   async function handleDelete() {
     if (!id) return;
     try {
@@ -247,6 +259,14 @@ export function TenantDetailPage() {
         {/* Actions */}
         <Card title="Actions">
           <div style={{ display: 'flex', flexDirection: 'column', gap: 10 }}>
+            <Button
+              variant="secondary"
+              onClick={handleRestart}
+              loading={restartServer.isPending}
+            >
+              <RefreshCw size={14} style={{ marginRight: 6 }} />
+              Restart Server
+            </Button>
             <Button
               variant="secondary"
               onClick={handleSuspendToggle}