refactor(desktop): centralize companion window ownership

Co-authored-by: Rizz <302abe414ca6e3134763d2539bfcf145aea2a63fe5f8455204ed602fd40cf381@buzz.block.builderlab.xyz>
Signed-off-by: Taylor Ho <taylorkmho@gmail.com>

desktop/src/app/AppShell.tsx

@@ -44,7 +44,7 @@ import {
 } from "@/features/notifications/hooks";
 import { PreventSleepProvider } from "@/features/agents/usePreventSleep";
 import { requestOpenCreateAgent } from "@/features/agents/openCreateAgentEvent";
-import { isAgentActivityWindow } from "@/features/agents/lib/agentActivityWindow";
+import { currentCompanionWindowKind } from "@/app/companionWindow";
 import { useAgentsDataRefresh } from "@/features/agents/lib/useAgentsDataRefresh";
 import { useManagedAgentRuntimeReconciliation } from "@/features/agents/useManagedAgentRuntimeReconciliation";
 import { useAutoRestartPolicy } from "@/features/agents/lib/useAutoRestartPolicy";
@@ -126,8 +126,9 @@ export function AppShell() {
     showHuddleInMainApp,
     viewHuddleChannel,
   } = useHuddlePresentation();
-  const isActivityWindow = isAgentActivityWindow();
-  const isCompanionWindow = isHuddleRoom || isActivityWindow;
+  const companionWindowKind = currentCompanionWindowKind();
+  const isActivityWindow = companionWindowKind === "agent-activity";
+  const isCompanionWindow = companionWindowKind !== null;
   const hasCommunityRail =
     communitiesHook.communities.length > 1 && !isCompanionWindow;
   const addCommunityDialog = useAddCommunityDialogState();
@@ -354,7 +355,7 @@ export function AppShell() {
     handleThreadReplyDesktopNotification,
   } = useAppShellDesktopNotifications({
     channels,
-    enabled: !isHuddleRoom,
+    enabled: !isCompanionWindow,
     goChannel,
     goHome,
     notificationSettings: notificationSettings.settings,
@@ -391,8 +392,8 @@ export function AppShell() {
     muteThread,
     unmuteThread,
   } = useUnreadChannels(
-    isHuddleRoom ? EMPTY_CHANNELS : sidebarChannels,
-    isHuddleRoom ? null : activeChannel,
+    isCompanionWindow ? EMPTY_CHANNELS : sidebarChannels,
+    isCompanionWindow ? null : activeChannel,
     {
       pubkey: identityQuery.data?.pubkey,
       relayClient,
@@ -454,7 +455,7 @@ export function AppShell() {
       identityQuery.data?.pubkey,
       notificationSettings.settings,
       notificationSettings.setDesktopEnabled,
-      !isHuddleRoom,
+      !isCompanionWindow,
       selectedView === "home" && !settingsOpen,
       getChannelReadAt,
       readStateVersion,
@@ -658,13 +659,13 @@ export function AppShell() {
     [openSearchHit],
   );
   useAppShellLifecycleEffects({
-    desktopBadgeEnabled: !isHuddleRoom,
+    desktopBadgeEnabled: !isCompanionWindow,
     homeBadgeCountExcludingHighPriority,
     topLevelUnreadChannelIds,
     unreadChannelNotificationCount,
   });
-  // Dispatch `buzz://` deep links only from the main window; the companion is dedicated to its active Huddle route.
-  useAppDeepLinks(!isHuddleRoom);
+  // Dispatch `buzz://` deep links only from the primary window; companions own their focused route.
+  useAppDeepLinks(!isCompanionWindow);
   const handleOpenCreateChannel = React.useCallback(
     () => setIsCreateChannelOpen(true),
     [],
@@ -673,7 +674,7 @@ export function AppShell() {
     activeChannelId: selectedView === "channel" ? selectedChannelId : null,
     canSearchCurrentChannel:
       selectedView === "channel" && Boolean(activeChannel),
-    disabled: settingsOpen || isHuddleRoom,
+    disabled: settingsOpen || isCompanionWindow,
     onBrowseChannels: handleOpenBrowseChannels,
     onCreateChannel: handleOpenCreateChannel,
     onGoHome: goHome,
@@ -684,7 +685,7 @@ export function AppShell() {
   useSettingsShortcuts({
     onClose: handleCloseSettings,
     onOpenSettings: handleOpenSettings,
-    open: isHuddleRoom ? undefined : settingsOpen,
+    open: isCompanionWindow ? undefined : settingsOpen,
   });
   useMarkAsReadShortcuts({
     activeChannelId: activeChannel?.id ?? null,

desktop/src/app/companionWindow.test.mjs

@@ -0,0 +1,19 @@
+import assert from "node:assert/strict";
+import { describe, it } from "node:test";
+
+import { companionWindowKindForLabel } from "./companionWindow.ts";
+
+describe("companionWindowKindForLabel", () => {
+  it("classifies focused companion labels", () => {
+    assert.equal(
+      companionWindowKindForLabel("agent-activity-deadbeef-channel"),
+      "agent-activity",
+    );
+    assert.equal(companionWindowKindForLabel("huddle-channel-id"), "huddle");
+  });
+
+  it("leaves primary and unrelated windows unclassified", () => {
+    assert.equal(companionWindowKindForLabel("main"), null);
+    assert.equal(companionWindowKindForLabel("reader-document"), null);
+  });
+});

desktop/src/app/companionWindow.ts

@@ -0,0 +1,30 @@
+import { isTauri } from "@tauri-apps/api/core";
+import { getCurrentWindow } from "@tauri-apps/api/window";
+
+export type CompanionWindowKind = "agent-activity" | "huddle";
+
+/** Classify native companion surfaces that reuse the main application shell. */
+export function companionWindowKindForLabel(
+  label: string,
+): CompanionWindowKind | null {
+  if (label.startsWith("agent-activity-")) return "agent-activity";
+  if (label.startsWith("huddle-")) return "huddle";
+  return null;
+}
+
+/** Return this webview's companion kind, or null for the primary app window. */
+export function currentCompanionWindowKind(): CompanionWindowKind | null {
+  if (!isTauri()) return null;
+
+  try {
+    return companionWindowKindForLabel(getCurrentWindow().label);
+  } catch {
+    // Browser previews can expose the Tauri IPC mock without window metadata.
+    return null;
+  }
+}
+
+/** Whether this webview is a focused companion rather than the primary app. */
+export function isCompanionWindow(): boolean {
+  return currentCompanionWindowKind() !== null;
+}

desktop/src/features/agents/lib/agentActivityWindow.ts

@@ -1,19 +1,9 @@
-import { isTauri } from "@tauri-apps/api/core";
+import { currentCompanionWindowKind } from "@/app/companionWindow";
 import { getCurrentWindow } from "@tauri-apps/api/window";
 
-const AGENT_ACTIVITY_WINDOW_LABEL_PREFIX = "agent-activity-";
-
 /** Whether this webview is dedicated to an agent activity feed. */
 export function isAgentActivityWindow(): boolean {
-  if (!isTauri()) return false;
-
-  try {
-    return getCurrentWindow().label.startsWith(
-      AGENT_ACTIVITY_WINDOW_LABEL_PREFIX,
-    );
-  } catch {
-    return false;
-  }
+  return currentCompanionWindowKind() === "agent-activity";
 }
 
 /** Build the concise native title for a channel-scoped activity window. */

desktop/src/main.tsx

@@ -11,8 +11,7 @@ import "@/shared/styles/globals.css";
 import { UpdaterProvider } from "@/features/settings/hooks/UpdaterProvider";
 import { migrateLegacyCommunityStorageBeforeRender } from "@/features/communities/legacyCommunityStorage";
 import { CommunitiesProvider } from "@/features/communities/useCommunities";
-import { huddleWindowChannelId } from "@/features/huddle/lib/huddleWindow";
-import { isAgentActivityWindow } from "@/features/agents/lib/agentActivityWindow";
+import { isCompanionWindow } from "@/app/companionWindow";
 import { CommunityOnboardingProvider } from "@/features/onboarding/communityOnboarding";
 import { ThemeProvider } from "@/shared/theme/ThemeProvider";
 import { EmojiBurstProvider } from "@/shared/ui/EmojiBurstProvider";
@@ -86,11 +85,7 @@ function renderApp() {
           SecurityError from localStorage can't blank the whole window. */}
       <RootErrorBoundary>
         <CommunitiesProvider>
-          <CommunityOnboardingProvider
-            enabled={
-              huddleWindowChannelId() === null && !isAgentActivityWindow()
-            }
-          >
+          <CommunityOnboardingProvider enabled={!isCompanionWindow()}>
             <ThemeProvider defaultTheme="buzz">
               <TooltipProvider>
                 <EmojiBurstProvider>