feat: add update indicators and stabilize Cursor streams

apps/desktop/src/store/updateStore.ts

@@ -0,0 +1,74 @@
+import { useSyncExternalStore } from "react";
+import type { Update } from "@tauri-apps/plugin-updater";
+import {
+  checkForUpdate,
+  hasNativeAppLifecycle,
+  installUpdate,
+} from "../native/appLifecycle";
+
+export type UpdateSnapshot = {
+  availableVersion: string | null;
+  checking: boolean;
+  installing: boolean;
+};
+
+let snapshot: UpdateSnapshot = {
+  availableVersion: null,
+  checking: false,
+  installing: false,
+};
+let availableUpdate: Update | null = null;
+let pendingCheck: Promise<string | null> | null = null;
+const listeners = new Set<() => void>();
+
+function update(patch: Partial<UpdateSnapshot>) {
+  snapshot = { ...snapshot, ...patch };
+  listeners.forEach((listener) => listener());
+}
+
+async function replaceAvailableUpdate(next: Update | null) {
+  const previous = availableUpdate;
+  availableUpdate = next;
+  update({ availableVersion: next?.version ?? null });
+  if (previous && previous !== next) await previous.close();
+}
+
+export const updateStore = {
+  subscribe(listener: () => void) {
+    listeners.add(listener);
+    return () => listeners.delete(listener);
+  },
+  getSnapshot: () => snapshot,
+
+  async check(): Promise<string | null> {
+    if (!hasNativeAppLifecycle()) return null;
+    if (pendingCheck) return pendingCheck;
+    update({ checking: true });
+    pendingCheck = (async () => {
+      const next = await checkForUpdate();
+      await replaceAvailableUpdate(next);
+      return next?.version ?? null;
+    })();
+    try {
+      return await pendingCheck;
+    } finally {
+      pendingCheck = null;
+      update({ checking: false });
+    }
+  },
+
+  async install(): Promise<void> {
+    const current = availableUpdate;
+    if (!current) return;
+    update({ installing: true });
+    try {
+      await installUpdate(current);
+    } finally {
+      update({ installing: false });
+    }
+  },
+};
+
+export function useUpdateStore(): UpdateSnapshot {
+  return useSyncExternalStore(updateStore.subscribe, updateStore.getSnapshot);
+}