fix: chat UI

lib/chat.ts

@@ -251,6 +251,10 @@ export const chat = {
    * Opens (or returns) the DM with a profile. Idempotent, and keyed by handle
    * because that is what a profile page has.
    */
+  /** Threads waiting on the caller. Muted ones are excluded — see the BFF. */
+  unreadCount: () =>
+    call<{ count: number }>("/chat/unread").then((r) => r.count),
+
   openDM: (handle: string) =>
     call<{ id: string; kind: ConversationKind }>("/chat/conversations/dm", {
       method: "POST",
@@ -589,6 +593,21 @@ export function followSummary(
 }
 
 /** Resolves a sender id to a display name using a thread's participants. */
+/**
+ * The participant who sent a message, or undefined for Kautilya, a system
+ * message, or someone who has since been removed.
+ *
+ * Groups need this rather than the conversation's `peer`: `peer` is only set
+ * on DMs, so a group has no single counterpart to read an avatar from.
+ */
+export function senderPeer(
+  senderId: string | null | undefined,
+  participants: ChatPeer[],
+): ChatPeer | undefined {
+  if (!senderId) return undefined;
+  return participants.find((p) => p.id === senderId);
+}
+
 export function senderName(
   senderId: string | null | undefined,
   participants: ChatPeer[],