[Bug]: Archived or deleted threads keep holding their devices #34173

diff --git a/apps/server/src/orchestration-v2/runtimeLayer.test.ts b/apps/server/src/orchestration-v2/runtimeLayer.test.ts
index a49e323770..bccb3db73c 100644
--- a/apps/server/src/orchestration-v2/runtimeLayer.test.ts
+++ b/apps/server/src/orchestration-v2/runtimeLayer.test.ts
@@ -87,6 +87,8 @@ import * as ScheduledTaskService from "../scheduledTasks/ScheduledTaskService.ts
 import * as ManagedPolicy from "../policy/ManagedPolicy.ts";
 import * as Scheduler from "../scheduling/Scheduler.ts";
 import * as SecretRequests from "../secrets/SecretRequests.ts";
+import * as DeviceHost from "../device/DeviceHost.ts";
+import * as DeviceService from "../device/DeviceService.ts";
 import * as PreviewManager from "../preview/Manager.ts";
 import * as TerminalManager from "../terminal/Manager.ts";
 import * as ResourceCleanupService from "./ResourceCleanupService.ts";
@@ -367,8 +369,59 @@ const layerScheduledTasksTest = ScheduledTaskService.layer.pipe(
     ),
   ),
 );
+const bootedSimulatorReady: DeviceHost.DeviceHostAgentReady = {
+  nodePath: process.execPath,
+  hub: { origin: "http://device.test" },
+  agentDevice: null,
+  helpers: { serveSimAxSettings: null, serveSimCli: null },
+  run: () => Effect.die("Thread cleanup must not run host commands"),
+  releaseAgentSession: () => Effect.void,
+  devices: {
+    list: Effect.succeed({
+      devices: [
+        {
+          id: "phone",
+          name: "iPhone",
+          platform: "ios",
+          version: "26",
+          booted: true,
+          physical: false,
+        },
+      ],
+      detail: undefined,
+    }),
+    boot: () => Effect.die("The simulator is already booted"),
+    attach: () => Effect.void,
+    shutdown: () => Effect.die("Thread cleanup must keep the simulator booted"),
+    screenshot: () => Effect.die("unused screenshot"),
+  },
+};
+const bootedSimulatorHost = DeviceHost.DeviceHost.of({
+  id: "local",
+  label: "Local",
+  summary: Effect.succeed({
+    id: "local",
+    label: "Local",
+    kind: "local",
+    hubInstalled: true,
+    agentDeviceInstalled: true,
+    platforms: [{ platform: "ios", available: true }],
+  }),
+  platformAvailability: (platform) => Effect.succeed({ platform, available: true }),
+  ensureReady: () => Effect.succeed(bootedSimulatorReady),
+  ensureAgentReady: () => Effect.succeed(bootedSimulatorReady),
+  current: Effect.succeed(bootedSimulatorReady),
+  stopAgent: Effect.void,
+  stop: Effect.void,
+});
 const layerResourceCleanupTest = ResourceCleanupService.layer.pipe(
   Layer.provideMerge(layerScheduledTasksTest),
+  Layer.provideMerge(
+    Layer.effect(
+      DeviceService.DeviceService,
+      DeviceService.makeWithHosts(new Map([[bootedSimulatorHost.id, bootedSimulatorHost]])),
+    ),
+  ),
   Layer.provide(
     Layer.mergeAll(
       Layer.mock(PreviewManager.PreviewManager)({ close: () => Effect.void }),
@@ -544,6 +597,61 @@ it.layer(layerProjectDeletionTest)("project deletion during thread commands", (i
       }),
   );
 
+  it.effect.each(["archive", "thread delete", "project delete"] as const)(
+    "%s releases the thread's devices and keeps them booted",
+    (lifecycle) =>
+      Effect.gen(function* () {
+        const projects = yield* ProjectService.ProjectService;
+        const orchestrator = yield* Orchestrator.OrchestratorV2;
+        const worker = yield* EffectWorker.OrchestrationEffectWorkerV2;
+        const devices = yield* DeviceService.DeviceService;
+        yield* devices.configure({ enabled: true, agentAccessEnabled: true });
+        const projectId = ProjectId.make(`device-cleanup-project:${lifecycle}`);
+        const threadId = ThreadId.make(`device-cleanup-thread:${lifecycle}`);
+        const otherThreadId = ThreadId.make(`device-surviving-thread:${lifecycle}`);
+        yield* projects.create({
+          commandId: CommandId.make(`device-cleanup-create-project:${lifecycle}`),
+          projectId,
+          title: "Device cleanup",
+          workspaceRoot: `/work/device-cleanup/${lifecycle}`,
+        });
+        for (const id of [threadId, otherThreadId]) {
+          yield* orchestrator.dispatch({
+            type: "thread.create",
+            commandId: CommandId.make(`device-cleanup-create:${id}`),
+            createdBy: "user",
+            creationSource: "web",
+            threadId: id,
+            projectId: id === threadId ? projectId : ProjectId.make("device-cleanup-other-project"),
+            title: "Device user",
+            modelSelection,
+            runtimeMode: "full-access",
+            interactionMode: "default",
+            branch: null,
+            worktreePath: null,
+          });
+          yield* devices.open({ threadId: id, deviceId: "phone", platform: "ios" });
+        }
+        const otherSessions = yield* devices.sessionsForThread(otherThreadId);
+
+        const commandId = CommandId.make(`device-cleanup:${lifecycle}`);
+        if (lifecycle === "project delete") {
+          yield* projects.delete({ commandId, projectId, force: true });
+        } else {
+          yield* orchestrator.dispatch({
+            type: lifecycle === "archive" ? "thread.archive" : "thread.delete",
+            commandId,
+            threadId,
+          });
+        }
+        yield* worker.drain();
+
+        assert.deepEqual(yield* devices.sessionsForThread(threadId), []);
+        assert.deepEqual(yield* devices.sessionsForThread(otherThreadId), otherSessions);
+        assert.isTrue((yield* devices.state).devices[0]?.booted);
+      }),
+  );
+
   it.effect("waits for an in-flight thread update before planning deletion", () =>
     Effect.gen(function* () {
       const projects = yield* ProjectService.ProjectService;