feat: Web Push für Logbuch-Eigner bei Crew-Sync

Benachrichtigt Owner optional per VAPID/Web Push, wenn Collaborators
Änderungen synchronisieren — ohne Klartext-Inhalte, mit Opt-in in den
Einstellungen, Custom Service Worker und Deep-Link zum Logbuch.

Co-authored-by: Cursor <cursoragent@cursor.com>

client/src/sw.ts

@@ -0,0 +1,73 @@
+/// <reference lib="webworker" />
+import { cleanupOutdatedCaches, precacheAndRoute } from 'workbox-precaching'
+
+declare let self: ServiceWorkerGlobalScope
+
+precacheAndRoute(self.__WB_MANIFEST)
+cleanupOutdatedCaches()
+
+interface PushPayload {
+  title?: string
+  body?: string
+  tag?: string
+  renotify?: boolean
+  data?: {
+    url?: string
+    logbookId?: string
+    changeCount?: number
+  }
+}
+
+self.addEventListener('push', (event) => {
+  event.waitUntil(
+    (async () => {
+      let payload: PushPayload = {}
+      try {
+        payload = event.data?.json() ?? {}
+      } catch {
+        payload = { body: event.data?.text() ?? '' }
+      }
+
+      const title = payload.title ?? 'Kapteins Daagbok'
+      const body = payload.body ?? ''
+      const data = payload.data ?? {}
+
+      await self.registration.showNotification(title, {
+        body,
+        tag: payload.tag,
+        icon: '/logo.png',
+        badge: '/logo.png',
+        data
+      })
+    })()
+  )
+})
+
+self.addEventListener('notificationclick', (event) => {
+  event.notification.close()
+  const data = (event.notification.data ?? {}) as PushPayload['data']
+  const targetPath = data?.url ?? '/'
+  const targetUrl = new URL(targetPath, self.location.origin).href
+
+  event.waitUntil(
+    (async () => {
+      const windowClients = await self.clients.matchAll({
+        type: 'window',
+        includeUncontrolled: true
+      })
+
+      for (const client of windowClients) {
+        if ('focus' in client) {
+          await client.focus()
+          client.postMessage({
+            type: 'OPEN_LOGBOOK',
+            logbookId: data?.logbookId
+          })
+          return
+        }
+      }
+
+      await self.clients.openWindow(targetUrl)
+    })()
+  )
+})