fix: enforce notification delivery authority

- Require active Guardian authority before cross-record delivery\n- Serialize managed delivery checks with lifecycle changes

src/__tests__/notification-delivery-identity.test.ts

@@ -1,5 +1,7 @@
 import { beforeEach, describe, expect, it, vi } from "vitest";
 
+const transactionMock = vi.fn();
+
 vi.mock("@/lib/db", () => ({
   prisma: {
     notificationChannel: {
@@ -9,6 +11,7 @@ vi.mock("@/lib/db", () => ({
     },
     user: { findUnique: vi.fn() },
     auditLog: { create: vi.fn() },
+    $transaction: (...args: unknown[]) => transactionMock(...args),
   },
 }));
 
@@ -76,6 +79,20 @@ beforeEach(() => {
   vi.mocked(prisma.notificationChannel.update).mockResolvedValue({
     consecutiveFailures: 0,
   } as never);
+  transactionMock.mockImplementation(
+    async (operation: (tx: unknown) => Promise<unknown>) =>
+      operation({
+        $queryRaw: vi.fn(),
+        user: {
+          findUnique: vi.fn(async ({ where }: { where: { id: string } }) =>
+            where.id === recordUserId
+              ? { managedProfileAt: new Date() }
+              : { managedProfileAt: null },
+          ),
+        },
+        accountGrant: { findFirst: vi.fn(async () => ({ id: "grant" })) },
+      }),
+  );
   sendViaWebPushMock.mockResolvedValue({ ok: true });
 });
 
@@ -110,6 +127,7 @@ describe("notification delivery identity", () => {
         message: "Record schedule",
       }),
     );
+    expect(transactionMock).toHaveBeenCalledTimes(1);
   });
 
   it("refuses a managed record without an explicit recipient", async () => {

src/lib/notifications/delivery-identity.ts

@@ -1,4 +1,8 @@
 import { prisma } from "@/lib/db";
+import {
+  activeGuardianWhere,
+  withManagedProfileLock,
+} from "@/lib/managed-profiles/lifecycle";
 import type { NotificationPayload } from "@/lib/notifications/types";
 
 export interface NotificationDeliveryIdentity {
@@ -10,7 +14,13 @@ export interface NotificationDeliveryIdentity {
 /**
  * Resolve notification identities without treating a managed record as its
  * own destination. Legacy payloads remain valid only for ordinary self
- * delivery; a managed record must name its recipient explicitly.
+ * delivery; a managed record must name an active Guardian explicitly.
+ *
+ * Cross-principal authorization linearizes at the locked grant read below,
+ * immediately before the dispatcher selects a channel. A revocation that
+ * commits before that read prevents delivery; one that commits afterwards
+ * affects later dispatches but cannot recall provider work already in flight.
+ * The provider call deliberately runs outside the short database transaction.
  */
 export async function resolveNotificationDeliveryIdentity(
   payload: NotificationPayload,
@@ -32,14 +42,35 @@ export async function resolveNotificationDeliveryIdentity(
   });
   if (!record) return null;
 
-  const managed = record.managedProfileAt != null;
-  if (managed) {
+  if (record.managedProfileAt == null) {
     return recipientUserId === recordUserId
-      ? null
-      : { recordUserId, recipientUserId, managed };
+      ? { recordUserId, recipientUserId, managed: false }
+      : null;
   }
 
-  return recipientUserId === recordUserId
-    ? { recordUserId, recipientUserId, managed }
-    : null;
+  if (recipientUserId === recordUserId) return null;
+
+  return prisma.$transaction(async (tx) =>
+    withManagedProfileLock(tx, recordUserId, async (lockedRecord) => {
+      if (lockedRecord?.managedProfileAt == null) return null;
+
+      const recipient = await tx.user.findUnique({
+        where: { id: recipientUserId },
+        select: { managedProfileAt: true },
+      });
+      if (!recipient || recipient.managedProfileAt != null) return null;
+
+      const guardian = await tx.accountGrant.findFirst({
+        where: {
+          grantorId: recordUserId,
+          granteeId: recipientUserId,
+          ...activeGuardianWhere(new Date()),
+        },
+        select: { id: true },
+      });
+      if (!guardian) return null;
+
+      return { recordUserId, recipientUserId, managed: true };
+    }),
+  );
 }

tests/integration/notification-attribution.test.ts

@@ -30,7 +30,7 @@ async function createGuardianGrant(input: {
       grantorId: input.recordUserId,
       granteeId: input.recipientUserId,
       access: input.access ?? "MANAGE",
-      acceptedAt: input.acceptedAt ?? new Date(),
+      acceptedAt: input.acceptedAt === undefined ? new Date() : input.acceptedAt,
       revokedAt: input.revokedAt ?? null,
       revokedBy: input.revokedAt ? "GRANTOR" : null,
       expiresAt: input.expiresAt ?? null,