feat(notifications): register FCM tokens with backend

Add registerToken POST to /notifications/register (platform, testMode).
Call it from Capacitor registration and Firebase getToken with deduped
registerRetrievedToken; expose registerToken via barrel and useNotifications
as registerFcmToken.

src/composables/useNotifications.ts

@@ -1,6 +1,7 @@
 /* eslint-disable @typescript-eslint/no-unused-vars */
 import { inject } from "vue";
 import { NotificationIface } from "../constants/app";
+import { registerToken } from "@/services/notifications/NotificationService";
 
 /**
  * Vue 3 composable for notifications
@@ -93,5 +94,7 @@ export function useNotifications() {
     notAGive,
     notificationOff,
     downloadStarted,
+    /** POST FCM token to `/notifications/register` (same as startup native hook). */
+    registerFcmToken: registerToken,
   };
 }

src/services/notifications/NotificationService.ts

@@ -14,9 +14,32 @@
  */
 
 import { Capacitor } from "@capacitor/core";
+import { logger } from "@/utils/logger";
 import { NativeNotificationService } from "./NativeNotificationService";
 import { WebPushNotificationService } from "./WebPushNotificationService";
 
+/**
+ * Registers an FCM device token with the app backend (native Capacitor token or web getToken).
+ */
+export async function registerToken(fcmToken: string): Promise<void> {
+  const res = await fetch("/notifications/register", {
+    method: "POST",
+    headers: { "Content-Type": "application/json" },
+    body: JSON.stringify({
+      fcmToken,
+      platform: Capacitor.getPlatform(),
+      testMode: true,
+    }),
+  });
+  if (!res.ok) {
+    logger.warn("[NotificationService] registerToken failed", {
+      status: res.status,
+      statusText: res.statusText,
+    });
+    throw new Error(`registerToken failed: HTTP ${res.status}`);
+  }
+}
+
 /**
  * Options for scheduling a daily notification
  */

src/services/notifications/firebaseMessagingClient.ts

@@ -21,11 +21,26 @@ import {
   onMessage,
 } from "firebase/messaging";
 import { logger } from "@/utils/logger";
+import { registerToken } from "./NotificationService";
 
 const LOG = "[FirebaseMessaging]";
 
 let firebaseAppSingleton: FirebaseApp | null = null;
 let nativeInitPromise: Promise<void> | null = null;
+/** Avoid duplicate POSTs when the same token is delivered more than once. */
+let lastRegisteredFcmToken: string | null = null;
+
+async function registerRetrievedToken(token: string): Promise<void> {
+  const trimmed = token.trim();
+  if (!trimmed) {
+    return;
+  }
+  if (trimmed === lastRegisteredFcmToken) {
+    return;
+  }
+  await registerToken(trimmed);
+  lastRegisteredFcmToken = trimmed;
+}
 
 function readFirebaseOptions(): FirebaseOptions | null {
   const env = import.meta.env;
@@ -107,6 +122,7 @@ async function attachFirebaseMessagingIfSupported(
     logger.info(`${LOG} Firebase getToken completed`, {
       tokenPrefix: token ? `${token.slice(0, 12)}…` : "(empty)",
     });
+    await registerRetrievedToken(token);
   } catch (err) {
     logger.warn(
       `${LOG} Firebase getToken failed (common on native WebView without SW)`,
@@ -135,6 +151,12 @@ async function initializeNativePushAndFirebaseMessagingImpl(): Promise<void> {
       logger.info(`${LOG} Capacitor registration token`, {
         valuePrefix: token.value ? `${token.value.slice(0, 12)}…` : "(empty)",
       });
+      void registerRetrievedToken(token.value).catch((err) => {
+        logger.warn(
+          `${LOG} registerToken after Capacitor registration failed`,
+          err,
+        );
+      });
     });
 
     await PushNotifications.addListener("registrationError", (err) => {

src/services/notifications/index.ts

@@ -13,7 +13,7 @@
  * ```
  */
 
-export { NotificationService } from "./NotificationService";
+export { NotificationService, registerToken } from "./NotificationService";
 export { NativeNotificationService } from "./NativeNotificationService";
 export { WebPushNotificationService } from "./WebPushNotificationService";