fix(desktop): preserve read state in activity windows

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

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

@@ -217,6 +217,7 @@ export function ChannelScreen({
     activeChannelId,
     activeChannel?.isMember,
     activeReadAt,
+    !isDedicatedActivityWindow,
   );
   React.useEffect(() => {
     if (!activeChannelId) {

desktop/src/features/channels/ui/useChannelOpenReadState.test.mjs

@@ -1,7 +1,10 @@
 import assert from "node:assert/strict";
 import test from "node:test";
 
-import { getTopLevelInboxUnreadOverrideIds } from "./useChannelOpenReadState.ts";
+import {
+  getTopLevelInboxUnreadOverrideIds,
+  shouldAdvanceChannelReadState,
+} from "./useChannelOpenReadState.ts";
 
 test("opening a channel clears only its top-level Inbox overrides", () => {
   assert.deepEqual(
@@ -23,3 +26,22 @@ test("opening a channel clears only its top-level Inbox overrides", () => {
     ["top-level"],
   );
 });
+
+test("passive activity companions never advance synced read state", () => {
+  assert.equal(
+    shouldAdvanceChannelReadState({
+      activeChannelId: "general",
+      enabled: false,
+      isChannelMember: true,
+    }),
+    false,
+  );
+  assert.equal(
+    shouldAdvanceChannelReadState({
+      activeChannelId: "general",
+      enabled: true,
+      isChannelMember: true,
+    }),
+    true,
+  );
+});

desktop/src/features/channels/ui/useChannelOpenReadState.ts

@@ -17,16 +17,29 @@ export function getTopLevelInboxUnreadOverrideIds(
   );
 }
 
+export function shouldAdvanceChannelReadState({
+  activeChannelId,
+  enabled,
+  isChannelMember,
+}: {
+  activeChannelId: string | null;
+  enabled: boolean;
+  isChannelMember: boolean | undefined;
+}): boolean {
+  return enabled && activeChannelId !== null && isChannelMember !== false;
+}
+
 export function useChannelOpenReadState(
   activeChannelId: string | null,
   isChannelMember: boolean | undefined,
   activeReadAt: string | null,
+  enabled = true,
 ) {
   const { feedItemState, locallyUnreadFeedItems, markChannelRead } =
     useAppShell();
 
   React.useEffect(() => {
-    if (!activeChannelId || isChannelMember === false) return;
+    if (!activeChannelId || !enabled || isChannelMember === false) return;
     for (const itemId of getTopLevelInboxUnreadOverrideIds(
       locallyUnreadFeedItems,
       activeChannelId,
@@ -37,6 +50,7 @@ export function useChannelOpenReadState(
   }, [
     activeChannelId,
     activeReadAt,
+    enabled,
     feedItemState.undoUnread,
     isChannelMember,
     locallyUnreadFeedItems,