Fix archived workspace session routing\n\nCloses #128

packages/app/src/screens/workspace/workspace-agent-visibility.test.ts

@@ -3,6 +3,7 @@ import type { Agent } from "@/stores/session-store";
 import {
   canOpenAgentTabFromRoute,
   deriveWorkspaceAgentVisibility,
+  shouldPruneWorkspaceAgentTab,
 } from "@/screens/workspace/workspace-agent-visibility";
 
 function makeAgent(input: {
@@ -104,6 +105,33 @@ describe("workspace agent visibility", () => {
     ).toBe(true);
   });
 
+  it("does not prune archived agent tabs when the workspace lookup still contains the agent", () => {
+    const archivedAgent = makeAgent({
+      id: "archived-agent",
+      cwd: "/repo/worktree",
+      archivedAt: new Date("2026-03-04T00:01:00.000Z"),
+    });
+    const lookup = new Map<string, Agent>([[archivedAgent.id, archivedAgent]]);
+
+    expect(
+      shouldPruneWorkspaceAgentTab({
+        agentId: "archived-agent",
+        agentsHydrated: true,
+        workspaceAgentLookup: lookup,
+      })
+    ).toBe(false);
+  });
+
+  it("prunes agent tabs once agents are hydrated and the agent is missing from the workspace lookup", () => {
+    expect(
+      shouldPruneWorkspaceAgentTab({
+        agentId: "missing-agent",
+        agentsHydrated: true,
+        workspaceAgentLookup: new Map<string, Agent>(),
+      })
+    ).toBe(true);
+  });
+
   it("sorts same-createdAt agents by lastActivityAt descending", () => {
     const workspaceId = "/repo/worktree";
     const createdAt = new Date("2026-03-04T00:00:00.000Z");