feat: add service worker cleanup to remove legacy registrations on startup

src/main.tsx

@@ -19,6 +19,22 @@ import AuthCallback from './pages/AuthCallback.tsx'
 import BlogPost from './pages/BlogPost.tsx'
 import EditPost from './pages/EditPost.tsx'
 
+// Ensure any legacy service workers from previous deployments are removed.
+if ('serviceWorker' in navigator) {
+  navigator.serviceWorker
+    .getRegistrations()
+    .then((registrations) => {
+      registrations.forEach((registration) => {
+        registration.unregister().catch(() => {
+          // Swallow errors since stale service workers are non-critical.
+        })
+      })
+    })
+    .catch(() => {
+      // Ignore lookup errors; the app functions without service workers.
+    })
+}
+
 createRoot(document.getElementById('root')!).render(
   <StrictMode>
     <ThemeProvider>