fix(inbox): reply at same thread level as inbox item (#1714)

Signed-off-by: Will Pfleger <pfleger.will@gmail.com>
Co-authored-by: npub1mn7jgtj4w2pd0g0zeuhxsa6jy6p0rewxz4kujt98my82ahfmp72sxjexk7 <dcfd242e557282d7a1e2cf2e6877522682f1e5c6156dc92ca7d90eaedd3b0f95@sprout-oss.stage.blox.sqprod.co>

desktop/src/features/home/ui/InboxDetailPane.tsx

@@ -18,6 +18,7 @@ import {
   hasSameMessageAuthor,
   isWithinGroupingWindow,
 } from "@/features/messages/lib/messageGrouping";
+import { getThreadReference } from "@/features/messages/lib/threading";
 import { MessageComposer } from "@/features/messages/ui/MessageComposer";
 import { UpdateIndicator } from "@/features/settings/UpdateIndicator";
 import type { Channel } from "@/shared/api/types";
@@ -208,7 +209,10 @@ export function InboxDetailPane({
         ];
   const replyTarget =
     displayMessages.find((message) => message.id === replyTargetId) ?? null;
-  const composerParentEventId = replyTarget?.id ?? item.id;
+  const composerParentEventId =
+    replyTarget?.id ??
+    getThreadReference(item.item.tags ?? []).parentId ??
+    item.id;
   const composerReplyTarget =
     replyTarget && replyTarget.id !== item.id
       ? {