feat: nevermind, migrate push notification handling from UnifiedPush to FCM

app/api/push/register/route.ts

@@ -1,45 +1,31 @@
 import { NextRequest, NextResponse } from 'next/server';
 import { logger } from '@/lib/logger';
 import { subscriptionStore } from '@/lib/push/store';
-import {
-  isValidAuthSecret,
-  isValidP256dh,
-  isValidPushEndpoint,
-  isValidSubscriptionId,
-} from '@/lib/push/validation';
+import { isValidFcmToken, isValidSubscriptionId } from '@/lib/push/validation';
 import type { SubscriptionRecord } from '@/lib/push/types';
 
 /**
  * POST /api/push/register
- * Body: { subscriptionId, endpoint, p256dh, auth, accountLabel? }
+ * Body: { subscriptionId, fcmToken, accountLabel? }
  *
- * Called by the mobile app once its UnifiedPush distributor has produced a
- * push endpoint. We hold only the Web Push keys needed to encrypt payloads
- * per RFC 8291 — no user credentials pass through the relay.
+ * Called by the mobile app once Firebase has issued an FCM registration
+ * token. The relay stores only the opaque token — no user credentials.
  */
 export async function POST(request: NextRequest) {
   try {
     const body = (await request.json().catch(() => null)) as {
       subscriptionId?: unknown;
-      endpoint?: unknown;
-      p256dh?: unknown;
-      auth?: unknown;
+      fcmToken?: unknown;
       accountLabel?: unknown;
     } | null;
     if (!body) return NextResponse.json({ error: 'Invalid JSON' }, { status: 400 });
 
-    const { subscriptionId, endpoint, p256dh, auth, accountLabel } = body;
+    const { subscriptionId, fcmToken, accountLabel } = body;
     if (!isValidSubscriptionId(subscriptionId)) {
       return NextResponse.json({ error: 'Invalid subscriptionId' }, { status: 400 });
     }
-    if (!isValidPushEndpoint(endpoint)) {
-      return NextResponse.json({ error: 'Invalid endpoint' }, { status: 400 });
-    }
-    if (!isValidP256dh(p256dh)) {
-      return NextResponse.json({ error: 'Invalid p256dh' }, { status: 400 });
-    }
-    if (!isValidAuthSecret(auth)) {
-      return NextResponse.json({ error: 'Invalid auth' }, { status: 400 });
+    if (!isValidFcmToken(fcmToken)) {
+      return NextResponse.json({ error: 'Invalid fcmToken' }, { status: 400 });
     }
 
     // Preserve verificationCode if a previous record exists — the JMAP server
@@ -47,9 +33,7 @@ export async function POST(request: NextRequest) {
     const existing = await subscriptionStore.get(subscriptionId);
 
     const record: SubscriptionRecord = {
-      endpoint,
-      p256dh,
-      auth,
+      fcmToken,
       verificationCode: existing?.verificationCode ?? null,
       createdAt: existing?.createdAt ?? Date.now(),
       lastPushAt: existing?.lastPushAt ?? null,