Fix notifications opening the wrong workspace (#2331)

* fix(app): open notifications on the right host

Agent notifications previously omitted workspace ownership, so a cold target host was treated as missing and fell back to its empty home route. Carry the authoritative workspace and keep older notifications on a target-host resolver until lookup is conclusive.

* fix(app): separate notification and agent URL routing

Notifications use their authoritative workspace target directly. Stable agent URLs remain server-and-agent targets whose workspace is resolved by the agent route.

* fix(protocol): preserve notification workspace targets

Both attention message variants retain workspaceId through outbound validation so notification clicks receive the authoritative route target.

* test(app): use workspace-scoped notification target

* test(server): give notification agents workspace targets

* test(app): target notification workspace in navigation e2e

packages/protocol/src/agent-attention-notification.ts

@@ -5,6 +5,7 @@ export type AgentAttentionReason = "finished" | "error" | "permission";
 export interface AgentAttentionNotificationData {
   [key: string]: unknown;
   serverId: string;
+  workspaceId?: string;
   agentId: string;
   reason: AgentAttentionReason;
 }
@@ -18,6 +19,7 @@ export interface AgentAttentionNotificationPayload {
 interface BuildAgentAttentionNotificationPayloadInput {
   reason: AgentAttentionReason;
   serverId: string;
+  workspaceId: string;
   agentId: string;
   assistantMessage?: string | null;
   permissionRequest?: NotificationPermissionRequest | null;
@@ -203,6 +205,7 @@ export function buildAgentAttentionNotificationPayload(
     body,
     data: {
       serverId: input.serverId,
+      workspaceId: input.workspaceId,
       agentId: input.agentId,
       reason: input.reason,
     },