fix(desktop): refine thread panel reply layout

Co-authored-by: Cursor <cursoragent@cursor.com>

desktop/src/features/messages/lib/threadPanel.test.mjs

@@ -1,7 +1,10 @@
 import assert from "node:assert/strict";
 import test from "node:test";
 
-import { buildMainTimelineEntries } from "./threadPanel.ts";
+import {
+  buildMainTimelineEntries,
+  buildThreadPanelData,
+} from "./threadPanel.ts";
 
 function message(overrides) {
   return {
@@ -56,3 +59,66 @@ test("buildMainTimelineEntries includes broadcast replies", () => {
     ["root", "broadcast-reply"],
   );
 });
+
+test("buildThreadPanelData keeps direct replies flat", () => {
+  const root = message({ id: "root", createdAt: 1 });
+  const reply = message({
+    id: "reply",
+    createdAt: 2,
+    parentId: "root",
+    rootId: "root",
+    depth: 1,
+    tags: [["e", "root", "", "reply"]],
+  });
+
+  const panel = buildThreadPanelData([root, reply], "root", null, new Set());
+
+  assert.deepEqual(
+    panel.visibleReplies.map((entry) => ({
+      id: entry.message.id,
+      depth: entry.message.depth,
+    })),
+    [{ id: "reply", depth: 0 }],
+  );
+});
+
+test("buildThreadPanelData indents expanded subthread replies", () => {
+  const root = message({ id: "root", createdAt: 1 });
+  const reply = message({
+    id: "reply",
+    createdAt: 2,
+    parentId: "root",
+    rootId: "root",
+    depth: 1,
+    tags: [["e", "root", "", "reply"]],
+  });
+  const nestedReply = message({
+    id: "nested-reply",
+    createdAt: 3,
+    parentId: "reply",
+    rootId: "root",
+    depth: 2,
+    tags: [
+      ["e", "root", "", "root"],
+      ["e", "reply", "", "reply"],
+    ],
+  });
+
+  const panel = buildThreadPanelData(
+    [root, reply, nestedReply],
+    "root",
+    null,
+    new Set(["reply"]),
+  );
+
+  assert.deepEqual(
+    panel.visibleReplies.map((entry) => ({
+      id: entry.message.id,
+      depth: entry.message.depth,
+    })),
+    [
+      { id: "reply", depth: 0 },
+      { id: "nested-reply", depth: 1 },
+    ],
+  );
+});

desktop/src/features/messages/lib/threadPanel.ts

@@ -207,7 +207,7 @@ function buildVisibleThreadReplies(params: {
   appendExpandedReplies({
     entries,
     parentId: openThreadHeadId,
-    depth: 1,
+    depth: 0,
     directChildrenByParentId,
     descendantStatsByMessageId,
     expandedReplyIds,

desktop/src/features/messages/ui/MessageRow.tsx

@@ -255,7 +255,7 @@ export const MessageRow = React.memo(
         <article
           className={cn(
             "group/message rounded-2xl px-2 py-1 transition-colors",
-            isThreadReplyLayout ? "space-y-1" : "flex items-start gap-2.5",
+            isThreadReplyLayout ? "space-y-0" : "flex items-start gap-2.5",
             highlighted ? "bg-primary/10 ring-1 ring-primary/30" : "",
           )}
           data-message-id={message.id}
@@ -298,7 +298,9 @@ export const MessageRow = React.memo(
                   </div>
                 </div>
               </div>
-              <div className="min-w-0 space-y-0.5">{messageBodyNode}</div>
+              <div className="-mt-0.5 min-w-0 space-y-0.5 pl-[26px]">
+                {messageBodyNode}
+              </div>
             </>
           ) : (
             <>