fix(desktop): trust electron-updater's isUpdateAvailable for the manual check

Per review: deriving `available` from a version-string compare is wrong —
`updateInfo.version` can differ from `app.getVersion()` while
electron-updater still suppresses `update-available` (pre-release channels,
staged rollouts, downgrade scenarios, min-system-version gates). In those
cases the settings tab would say "vX is available" but no corner download
prompt would ever appear. Use `result?.isUpdateAvailable` instead, which is
electron-updater's own answer.

apps/desktop/src/main/updater.ts

@@ -1,9 +1,21 @@
 import { autoUpdater } from "electron-updater";
-import { BrowserWindow, ipcMain } from "electron";
+import { app, BrowserWindow, ipcMain } from "electron";
 
 autoUpdater.autoDownload = false;
 autoUpdater.autoInstallOnAppQuit = true;
 
+const STARTUP_CHECK_DELAY_MS = 5_000;
+const PERIODIC_CHECK_INTERVAL_MS = 60 * 60 * 1000; // 1 hour
+
+export type ManualUpdateCheckResult =
+  | {
+      ok: true;
+      currentVersion: string;
+      latestVersion: string;
+      available: boolean;
+    }
+  | { ok: false; error: string };
+
 export function setupAutoUpdater(getMainWindow: () => BrowserWindow | null): void {
   autoUpdater.on("update-available", (info) => {
     const win = getMainWindow();
@@ -37,10 +49,42 @@ export function setupAutoUpdater(getMainWindow: () => BrowserWindow | null): voi
     autoUpdater.quitAndInstall(false, true);
   });
 
-  // Check for updates after a short delay to avoid blocking startup
+  ipcMain.handle("updater:check", async (): Promise<ManualUpdateCheckResult> => {
+    try {
+      const result = await autoUpdater.checkForUpdates();
+      const currentVersion = app.getVersion();
+      // Trust electron-updater's own decision rather than re-deriving it from
+      // a version-string compare. The two diverge for pre-release channels,
+      // staged rollouts, downgrades, and minimum-system-version gates — in
+      // those cases updateInfo.version differs from app.getVersion() but no
+      // `update-available` event fires, so showing "available" here would
+      // promise a download prompt that never appears.
+      return {
+        ok: true,
+        currentVersion,
+        latestVersion: result?.updateInfo.version ?? currentVersion,
+        available: result?.isUpdateAvailable ?? false,
+      };
+    } catch (err) {
+      return {
+        ok: false,
+        error: err instanceof Error ? err.message : String(err),
+      };
+    }
+  });
+
+  // Initial check shortly after startup so we don't block boot.
   setTimeout(() => {
     autoUpdater.checkForUpdates().catch((err) => {
       console.error("Failed to check for updates:", err);
     });
-  }, 5000);
+  }, STARTUP_CHECK_DELAY_MS);
+
+  // Background poll so long-running sessions still pick up new releases
+  // without requiring the user to restart the app.
+  setInterval(() => {
+    autoUpdater.checkForUpdates().catch((err) => {
+      console.error("Periodic update check failed:", err);
+    });
+  }, PERIODIC_CHECK_INTERVAL_MS);
 }

apps/desktop/src/preload/index.d.ts

@@ -53,6 +53,10 @@ interface UpdaterAPI {
   onUpdateDownloaded: (callback: () => void) => () => void;
   downloadUpdate: () => Promise<void>;
   installUpdate: () => Promise<void>;
+  checkForUpdates: () => Promise<
+    | { ok: true; currentVersion: string; latestVersion: string; available: boolean }
+    | { ok: false; error: string }
+  >;
 }
 
 declare global {

apps/desktop/src/preload/index.ts

@@ -96,6 +96,10 @@ const updaterAPI = {
   },
   downloadUpdate: () => ipcRenderer.invoke("updater:download"),
   installUpdate: () => ipcRenderer.invoke("updater:install"),
+  checkForUpdates: (): Promise<
+    | { ok: true; currentVersion: string; latestVersion: string; available: boolean }
+    | { ok: false; error: string }
+  > => ipcRenderer.invoke("updater:check"),
 };
 
 if (process.contextIsolated) {

apps/desktop/src/renderer/src/components/updates-settings-tab.tsx

@@ -0,0 +1,86 @@
+import { useCallback, useState } from "react";
+import { AlertCircle, ArrowDownToLine, Check, Loader2 } from "lucide-react";
+import { Button } from "@multica/ui/components/ui/button";
+
+type CheckState =
+  | { status: "idle" }
+  | { status: "checking" }
+  | { status: "up-to-date"; currentVersion: string }
+  | { status: "available"; latestVersion: string }
+  | { status: "error"; message: string };
+
+export function UpdatesSettingsTab() {
+  const [state, setState] = useState<CheckState>({ status: "idle" });
+
+  const handleCheck = useCallback(async () => {
+    setState({ status: "checking" });
+    const result = await window.updater.checkForUpdates();
+    if (!result.ok) {
+      setState({ status: "error", message: result.error });
+      return;
+    }
+    setState(
+      result.available
+        ? { status: "available", latestVersion: result.latestVersion }
+        : { status: "up-to-date", currentVersion: result.currentVersion },
+    );
+  }, []);
+
+  return (
+    <div>
+      <h2 className="text-lg font-semibold">Updates</h2>
+      <p className="text-sm text-muted-foreground mt-1">
+        The desktop app checks for new versions automatically once an hour and
+        shortly after launch.
+      </p>
+
+      <div className="mt-6 divide-y">
+        <div className="flex items-start justify-between gap-6 py-4">
+          <div className="min-w-0">
+            <p className="text-sm font-medium">Check for updates</p>
+            <p className="text-sm text-muted-foreground mt-0.5">
+              Trigger a check now instead of waiting for the next automatic
+              poll. Available updates appear as a notification in the corner.
+            </p>
+            {state.status === "up-to-date" && (
+              <p className="text-sm text-muted-foreground mt-2 inline-flex items-center gap-1.5">
+                <Check className="size-3.5 text-success" />
+                You&apos;re on the latest version (v{state.currentVersion}).
+              </p>
+            )}
+            {state.status === "available" && (
+              <p className="text-sm text-muted-foreground mt-2 inline-flex items-center gap-1.5">
+                <ArrowDownToLine className="size-3.5 text-primary" />
+                v{state.latestVersion} is available — see the download prompt
+                in the corner.
+              </p>
+            )}
+            {state.status === "error" && (
+              <p className="text-sm text-destructive mt-2 inline-flex items-center gap-1.5">
+                <AlertCircle className="size-3.5" />
+                {state.message}
+              </p>
+            )}
+          </div>
+          <div className="shrink-0">
+            <Button
+              variant="outline"
+              size="sm"
+              onClick={handleCheck}
+              disabled={state.status === "checking"}
+            >
+              {state.status === "checking" ? (
+                <>
+                  <Loader2 className="size-3.5 animate-spin" />
+                  Checking…
+                </>
+              ) : (
+                "Check now"
+              )}
+            </Button>
+          </div>
+        </div>
+      </div>
+    </div>
+  );
+}

apps/desktop/src/renderer/src/routes.tsx

@@ -19,8 +19,9 @@ import { DaemonRuntimeCard } from "./components/daemon-runtime-card";
 import { AgentsPage } from "@multica/views/agents";
 import { InboxPage } from "@multica/views/inbox";
 import { SettingsPage } from "@multica/views/settings";
-import { Server } from "lucide-react";
+import { Download, Server } from "lucide-react";
 import { DaemonSettingsTab } from "./components/daemon-settings-tab";
+import { UpdatesSettingsTab } from "./components/updates-settings-tab";
 import { WorkspaceRouteLayout } from "./components/workspace-route-layout";
 
 /**
@@ -130,6 +131,12 @@ export const appRoutes: RouteObject[] = [
                     icon: Server,
                     content: <DaemonSettingsTab />,
                   },
+                  {
+                    value: "updates",
+                    label: "Updates",
+                    icon: Download,
+                    content: <UpdatesSettingsTab />,
+                  },
                 ]}
               />
             ),