Version banner, File locations section, final CSP (no unsafe-inline styles, frame-src none, object-src none)

The MTR viewer draws PDFs with pdf.js instead of an iframe the server's frame-ancestors refused.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

frontend/src/components/VersionBanner.tsx

@@ -0,0 +1,19 @@
+import { useBuildChanged, type BuildWatchOptions } from "../lib/buildWatch";
+
+export const UPDATED_TEXT = "Packet Station was updated. Reload to get the new version.";
+
+const reloadPage = () => window.location.reload();
+
+/** A strip across the top when the server build changed since this page loaded. Reload is the user's call. */
+export function VersionBanner({ onReload = reloadPage, ...opts }: BuildWatchOptions & { onReload?: () => void }) {
+  const changed = useBuildChanged(opts);
+  if (!changed) return null;
+  return (
+    <div className="vbanner" role="status" data-testid="version-banner">
+      <span>{UPDATED_TEXT}</span>
+      <button className="btn sm pri" type="button" onClick={onReload}>
+        Reload
+      </button>
+    </div>
+  );
+}