fix(sw): ship self-unregistering tombstone to kill stale Void 1 service worker

public/sw.js

@@ -0,0 +1,30 @@
+// Self-unregistering "tombstone" service worker.
+//
+// Void 1 ran at this same origin (void.hynesy.com) and registered a caching
+// service worker at /sw.js. Void 2 ships NO service worker, so that old worker
+// would otherwise persist forever in returning visitors' browsers, intercepting
+// fetches and serving stale assets that even a hard reload cannot bypass.
+//
+// Serving this self-destructing worker at the same /sw.js URL means the browser's
+// periodic SW update check (which bypasses the HTTP cache and is not intercepted
+// by the old worker) replaces the old worker with this one. On activation it
+// wipes every cache, unregisters itself, and reloads open tabs — after which the
+// page loads fresh from the network with no controlling service worker.
+//
+// Keep serving this indefinitely so any device that ever ran Void 1 self-heals.
+
+self.addEventListener('install', () => self.skipWaiting());
+
+self.addEventListener('activate', (event) => {
+  event.waitUntil((async () => {
+    try {
+      const keys = await caches.keys();
+      await Promise.all(keys.map((k) => caches.delete(k)));
+    } catch (_) { /* best effort */ }
+    try { await self.registration.unregister(); } catch (_) { /* best effort */ }
+    const clients = await self.clients.matchAll({ type: 'window' });
+    for (const client of clients) {
+      try { client.navigate(client.url); } catch (_) { /* best effort */ }
+    }
+  })());
+});