Add device inventory refresh endpoint and auto-refresh UI

src/server/services/deviceInventoryService.js

@@ -66,6 +66,8 @@ function deviceStatus(lastSeenAt, now) {
 }
 
 export function createDeviceInventoryService({ store, observe, vendor = () => null, now = () => new Date() }) {
+  let refreshPromise = null;
+
   function snapshot() {
     const state = migrate(store.read());
     const current = now();
@@ -89,7 +91,7 @@ export function createDeviceInventoryService({ store, observe, vendor = () => nu
     };
   }
 
-  async function refresh() {
+  async function performRefresh() {
     let result;
     try {
       result = await observe();
@@ -138,6 +140,15 @@ export function createDeviceInventoryService({ store, observe, vendor = () => nu
     return snapshot();
   }
 
+  function refresh() {
+    if (!refreshPromise) {
+      refreshPromise = performRefresh().finally(() => {
+        refreshPromise = null;
+      });
+    }
+    return refreshPromise;
+  }
+
   function update(id, patch, expectedRevision) {
     if (!patch || typeof patch !== 'object' || Array.isArray(patch)) {
       throw new HarborError('REQUEST_INVALID');