fix(desktop): sync derived active-turn liveness in channel activity path

Rebased from tho/active-turn-bridge-fix (#1492) onto post-#1380 main,
squashing the temporary debug-harness add/remove churn that netted to
zero. Behavior preserved:

- ChannelScreen mounts useActiveAgentTurnsBridge next to the existing
  observer bridge so raw observer frames (e.g. turn_completed) and the
  derived liveness store stay in sync in the channel activity path
- Extract syncActiveAgentTurnsFromObserver() from the bridge hook so the
  regression test drives the exact observer→derived-liveness path
- resetActiveAgentTurnsStore() wired into workspace-switch reset per the
  workspace-switching singleton contract
- Regression coverage: observer→active-turns bridge sync keeps the raw
  feed's completion event while derived liveness clears; non-running
  agents don't populate the store

Co-authored-by: Taylor Ho <taylorkmho@gmail.com>
Signed-off-by: Taylor Ho <taylorkmho@gmail.com>

desktop/src/features/agents/activeAgentTurnsStore.test.mjs

@@ -3,11 +3,17 @@ import { describe, it, beforeEach, afterEach, mock } from "node:test";
 
 import {
   syncAgentTurnsFromEvents,
+  syncActiveAgentTurnsFromObserver,
   getActiveTurnsForAgent,
   getActiveTurnsByChannel,
   resetActiveAgentTurnsStore,
   subscribeActiveAgentTurns,
 } from "./activeAgentTurnsStore.ts";
+import {
+  injectObserverEventsForE2E,
+  getAgentObserverSnapshot,
+  resetAgentObserverStore,
+} from "./observerRelayStore.ts";
 import { formatElapsed } from "./ui/agentSessionUtils.ts";
 
 const AGENT =
@@ -1230,6 +1236,71 @@ describe("activeAgentTurnsStore", () => {
   });
 });
 
+/**
+ * Regression: raw observer ingestion and derived active-turn liveness must
+ * stay in sync. The channel activity path previously mounted only the observer
+ * bridge, so a raw `turn_completed` could be visible in the activity feed
+ * while the derived liveness indicator kept spinning. This drives events
+ * through the real observer store (appendAgentEvent path) and the same sync
+ * the bridge hook runs, asserting derived liveness clears with the raw feed.
+ */
+describe("observer → active-turns bridge sync", () => {
+  const bridgeAgents = [{ pubkey: AGENT, status: "deployed" }];
+
+  beforeEach(() => {
+    resetActiveAgentTurnsStore();
+    resetAgentObserverStore();
+  });
+
+  afterEach(() => {
+    resetAgentObserverStore();
+  });
+
+  it("clears derived liveness when raw turn_completed arrives", () => {
+    injectObserverEventsForE2E(AGENT, [
+      makeEvent({ seq: 1, kind: "turn_started" }),
+    ]);
+    syncActiveAgentTurnsFromObserver(bridgeAgents);
+    assert.ok(
+      channelIdsOf(getActiveTurnsForAgent(AGENT)).has("chan-1"),
+      "turn_started must surface an active turn",
+    );
+
+    injectObserverEventsForE2E(AGENT, [
+      makeEvent({
+        seq: 2,
+        kind: "turn_completed",
+        timestamp: "2024-01-01T00:00:05Z",
+      }),
+    ]);
+    syncActiveAgentTurnsFromObserver(bridgeAgents);
+
+    const rawEvents = getAgentObserverSnapshot(AGENT, true).events;
+    assert.equal(
+      rawEvents.at(-1)?.kind,
+      "turn_completed",
+      "raw feed must contain the completion event",
+    );
+    assert.equal(
+      getActiveTurnsForAgent(AGENT).length,
+      0,
+      "derived liveness must clear when the raw feed shows turn_completed",
+    );
+  });
+
+  it("skips agents that are neither running nor deployed", () => {
+    injectObserverEventsForE2E(AGENT, [
+      makeEvent({ seq: 1, kind: "turn_started" }),
+    ]);
+    syncActiveAgentTurnsFromObserver([{ pubkey: AGENT, status: "stopped" }]);
+    assert.equal(
+      getActiveTurnsForAgent(AGENT).length,
+      0,
+      "inactive agents must not populate the active-turns store",
+    );
+  });
+});
+
 describe("formatElapsed", () => {
   it("renders sub-10s as whole seconds", () => {
     assert.equal(formatElapsed(0), "0s");

desktop/src/features/agents/activeAgentTurnsStore.ts

@@ -527,6 +527,21 @@ export function useActiveAgentTurnsByChannel(): ActiveChannelTurnSummary[] {
   );
 }
 
+/**
+ * Sync every running/deployed agent's observer events into the active-turns
+ * store. Extracted from the bridge hook so a regression can drive the exact
+ * observer→derived-liveness path without a React renderer.
+ */
+export function syncActiveAgentTurnsFromObserver(
+  agents: readonly { pubkey: string; status: string }[],
+) {
+  for (const agent of agents) {
+    if (agent.status !== "running" && agent.status !== "deployed") continue;
+    const snapshot = getAgentObserverSnapshot(agent.pubkey, true);
+    syncAgentTurnsFromEvents(agent.pubkey, snapshot.events);
+  }
+}
+
 /**
  * Bridge hook: processes observer events into the active-turns store.
  * Should be called by a parent component that has access to the observer events.
@@ -536,11 +551,7 @@ export function useActiveAgentTurnsBridge(
 ) {
   React.useEffect(() => {
     function syncAll() {
-      for (const agent of agents) {
-        if (agent.status !== "running" && agent.status !== "deployed") continue;
-        const snapshot = getAgentObserverSnapshot(agent.pubkey, true);
-        syncAgentTurnsFromEvents(agent.pubkey, snapshot.events);
-      }
+      syncActiveAgentTurnsFromObserver(agents);
     }
 
     syncAll();

desktop/src/features/channels/ui/ChannelScreen.tsx

@@ -24,6 +24,7 @@ import {
   usePersonasQuery,
   useRelayAgentsQuery,
 } from "@/features/agents/hooks";
+import { useActiveAgentTurnsBridge } from "@/features/agents/activeAgentTurnsStore";
 import { useManagedAgentObserverBridge } from "@/features/agents/observerRelayStore";
 import {
   mergeMessages,
@@ -386,6 +387,11 @@ export function ChannelScreen({
     ];
   }, [managedAgents, openAgentSessionPubkey, profilePanelPubkey]);
   useManagedAgentObserverBridge(observerBridgeAgents);
+  // Derive active-turn/liveness state from the same observer events. Without
+  // this, raw observer frames (e.g. turn_completed) reach the activity panel
+  // while the derived active-turns store stays stale, leaving the liveness
+  // indicator spinning after the turn already finished.
+  useActiveAgentTurnsBridge(observerBridgeAgents);
   const messageProfiles = React.useMemo(() => {
     const base =
       mergeCurrentProfileIntoLookup(

desktop/src/features/workspaces/useWorkspaceInit.ts

@@ -10,6 +10,7 @@ import { resetMediaCaches } from "@/shared/lib/mediaUrl";
 import { clearSearchHitEventCache } from "@/app/navigation/searchHitEventCache";
 import { clearAllDrafts } from "@/features/messages/lib/useDrafts";
 import { resetRenderScopedReactionHydration } from "@/features/messages/lib/renderScopedReactions";
+import { resetActiveAgentTurnsStore } from "@/features/agents/activeAgentTurnsStore";
 import { resetAgentObserverStore } from "@/features/agents/observerRelayStore";
 import { resetSidebarRelayConnectionCardState } from "@/features/sidebar/ui/useSidebarRelayConnectionCard";
 import { resetVideoPlayerState } from "@/shared/ui/videoPlayerState";
@@ -27,6 +28,7 @@ import type { Workspace } from "./types";
 function resetWorkspaceState(): void {
   relayClient.disconnect();
   resetAgentObserverStore();
+  resetActiveAgentTurnsStore();
   resetSidebarRelayConnectionCardState();
   resetMediaCaches();
   resetVideoPlayerState();