fix: rebuild propre — 1 seul bundle, plugin clean-assets avant chaque build

backend/public/sw.js

@@ -0,0 +1,42 @@
+// Service Worker — Sargasse-Sentry push notifications
+self.addEventListener('push', (event) => {
+  if (!event.data) return;
+
+  let payload;
+  try {
+    payload = event.data.json();
+  } catch {
+    payload = { title: 'Alerte sargasses', body: event.data.text() };
+  }
+
+  const title   = payload.title ?? 'Alerte sargasses';
+  const options = {
+    body:  payload.body ?? '',
+    icon:  '/icons.svg',
+    badge: '/icons.svg',
+    tag:   payload.spotId ? `sargasse-${payload.spotId}` : 'sargasse-alert',
+    renotify: true,
+    data: { url: payload.url ?? '/' },
+  };
+
+  event.waitUntil(self.registration.showNotification(title, options));
+});
+
+self.addEventListener('notificationclick', (event) => {
+  event.notification.close();
+
+  const targetUrl = event.notification.data?.url ?? '/';
+
+  event.waitUntil(
+    clients.matchAll({ type: 'window', includeUncontrolled: true }).then((windowClients) => {
+      for (const client of windowClients) {
+        if (client.url === targetUrl && 'focus' in client) {
+          return client.focus();
+        }
+      }
+      if (clients.openWindow) {
+        return clients.openWindow(targetUrl);
+      }
+    })
+  );
+});