feat(desktop): show the installed app's own version in the UI

Nothing displayed which desktop build was actually installed — debugging
a stuck update meant inferring the current version backwards from the
update prompt's target version. Added DesktopVersionBadge (next to the
existing server-side VersionBadge) using @tauri-apps/api's getVersion(),
the real running app version baked in from tauri.conf.json. No-ops in a
browser. Exported inTauri() from origin.ts instead of redefining it again.

apps/web/src/lib/origin.ts

@@ -39,7 +39,7 @@ export function wsUrl(path: string): string {
 }
 
 /** True when running inside the Tauri webview (not a normal browser). */
-function inTauri(): boolean {
+export function inTauri(): boolean {
   return typeof window !== "undefined" && "__TAURI_INTERNALS__" in window;
 }
 

apps/web/src/router.tsx

@@ -6,7 +6,7 @@ import {
   Outlet,
   redirect,
 } from "@tanstack/react-router";
-import { lazy, Suspense, useState } from "react";
+import { lazy, Suspense, useEffect, useState } from "react";
 import { useTranslation } from "react-i18next";
 import { useQuery, useQueryClient } from "@tanstack/react-query";
 import type { Lang, Permission, SessionUser, Theme } from "./api.js";
@@ -30,6 +30,7 @@ import { Spinner } from "./ui/Spinner.js";
 import { setLanguage } from "./lib/i18n/index.js";
 import { applyTheme, applyFontScale } from "./lib/theme.js";
 import { useLiveFeed } from "./lib/use-live-feed.js";
+import { inTauri } from "./lib/origin.js";
 import { useShift } from "./lib/use-shift.js";
 import { DeviceFooter } from "./ui/DeviceFooter.js";
 import { StatusDot } from "./ui/StatusDot.js";
@@ -106,6 +107,29 @@ function VersionBadge() {
   return <span className="ml-auto shrink-0 pl-3 text-[0.7rem] text-term-muted">{version}</span>;
 }
 
+/** The installed Tauri app's own "vX.Y.Z" (from tauri.conf.json, synced to the git tag by
+ *  release.yml — see wiki/decisions/desktop-shell-tauri.md) — the client's version, distinct
+ *  from VersionBadge's SERVER build. No-op / renders nothing in a browser (there's no Tauri
+ *  API to call). Was invisible before this: an operator had no way to tell which desktop
+ *  build was actually installed short of reading the update-available prompt. */
+function DesktopVersionBadge() {
+  const [version, setVersion] = useState<string | null>(null);
+  useEffect(() => {
+    if (!inTauri()) return;
+    let cancelled = false;
+    void import("@tauri-apps/api/app").then(({ getVersion }) =>
+      getVersion().then((v) => {
+        if (!cancelled) setVersion(v);
+      }),
+    );
+    return () => {
+      cancelled = true;
+    };
+  }, []);
+  if (!version) return null;
+  return <span className="ml-auto shrink-0 pl-3 text-[0.7rem] text-term-muted">app v{version}</span>;
+}
+
 /** Setup layout — the config hub. Renders a permission-gated tab bar and the active
  *  tab's screen via <Outlet>. Each tab is a child route (its own URL + guard), so
  *  deep links and the back button work and a denied tab redirects to the booth. */
@@ -125,6 +149,7 @@ function SetupLayout() {
         {show("log:read") && <SetupTab to="/setup/logs" label={t("nav.logs")} />}
         {show("backup:read") && <SetupTab to="/setup/backup" label={t("nav.backup")} />}
         {show("site:read") && <VersionBadge />}
+        <DesktopVersionBadge />
       </nav>
       <Outlet />
     </div>