fix(agent): bound push suppression to observed browser attention

server/prisma/migrations/20261015010000_bound_agent_push_attention/migration.sql

@@ -0,0 +1,5 @@
+ALTER TABLE "AgentPushPresence" ADD COLUMN "inactiveUntil" DATETIME;
+ALTER TABLE "AgentPushCoordinator" ADD COLUMN "unknownSince" DATETIME;
+ALTER TABLE "AgentPushDelivery" ADD COLUMN "lastSuppressionReason" TEXT;
+ALTER TABLE "AgentPushDelivery" ADD COLUMN "lastSuppressionClientKind" TEXT;
+ALTER TABLE "AgentPushDelivery" ADD COLUMN "lastSuppressedAt" DATETIME;

server/prisma/schema.prisma

@@ -249,6 +249,7 @@ model AgentPushPresence {
   visible           Boolean
   focused           Boolean
   lastInteractionAt DateTime?
+  inactiveUntil     DateTime?
   expiresAt         DateTime
   @@index([ownerEpoch, expiresAt])
 }
@@ -273,6 +274,7 @@ model AgentPushCoordinator {
   localPromptAt       DateTime?
   nativeActive        Boolean @default(false)
   nativeUnknown       Boolean @default(true)
+  unknownSince        DateTime?
   uncertain           Boolean @default(true)
   lockOwner           String?
   lockUntil           DateTime?
@@ -296,6 +298,9 @@ model AgentPushDelivery {
   expiresAt           DateTime
   updatedAt           DateTime @updatedAt
   outcome             String?
+  lastSuppressionReason     String?
+  lastSuppressionClientKind String?
+  lastSuppressedAt          DateTime?
   @@index([status, dueAt])
   @@index([installationId, status])
   @@index([ownerEpoch, sourceId, cursor])