feat: add webpush and sadhna tracker

public/sw.js

@@ -0,0 +1,48 @@
+/* Prabhupāda Says — Web Push service worker.
+ *
+ * Handles incoming push messages (shows a notification) and clicks (focuses
+ * an existing tab or opens the target URL). The push payload is the JSON the
+ * BFF sends: { title, body, url, icon, tag }.
+ */
+
+self.addEventListener("install", () => self.skipWaiting());
+self.addEventListener("activate", (event) =>
+  event.waitUntil(self.clients.claim()),
+);
+
+self.addEventListener("push", (event) => {
+  let data = {};
+  try {
+    data = event.data ? event.data.json() : {};
+  } catch {
+    data = { body: event.data && event.data.text ? event.data.text() : "" };
+  }
+  const title = data.title || "Prabhupāda Says";
+  const options = {
+    body: data.body || "",
+    icon: data.icon || "/logo_dark.png",
+    badge: "/logo_dark.png",
+    tag: data.tag || undefined,
+    data: { url: data.url || "/" },
+  };
+  event.waitUntil(self.registration.showNotification(title, options));
+});
+
+self.addEventListener("notificationclick", (event) => {
+  event.notification.close();
+  const url =
+    (event.notification.data && event.notification.data.url) || "/";
+  event.waitUntil(
+    self.clients
+      .matchAll({ type: "window", includeUncontrolled: true })
+      .then((list) => {
+        for (const client of list) {
+          if ("focus" in client) {
+            if ("navigate" in client) client.navigate(url);
+            return client.focus();
+          }
+        }
+        if (self.clients.openWindow) return self.clients.openWindow(url);
+      }),
+  );
+});