fix: allow notification nonce reuse per user

prisma/migrations/20250514193830_allow_notification_nonce_reuse_per_user/migration.sql

@@ -0,0 +1,11 @@
+/*
+  Warnings:
+
+  - A unique constraint covering the columns `[userId,nonce]` on the table `Notification` will be added. If there are existing duplicate values, this will fail.
+
+*/
+-- DropIndex
+DROP INDEX "Notification_nonce_key";
+
+-- CreateIndex
+CREATE UNIQUE INDEX "Notification_userId_nonce_key" ON "Notification"("userId", "nonce");

prisma/models/user.prisma

@@ -24,7 +24,7 @@ model User {
 model Notification {
     id String @id @default(uuid())
 
-    nonce String? @unique
+    nonce String?
 
     userId String
     user   User   @relation(fields: [userId], references: [id])
@@ -35,4 +35,6 @@ model Notification {
     actions     String[]
 
     read Boolean @default(false)
+
+    @@unique([userId, nonce])
 }