fix: chat — group members endpoint (all roles), mention first-name only, restore direct-chat button

src/lib/api.ts

@@ -356,6 +356,8 @@ export const api = {
       req<{ ok: boolean }>('PATCH', `/api/hotels/${slug}/chat/rooms/${roomId}/read`),
     openDirect: (slug: string, otherUserId: string) =>
       req<{ roomId: string }>('POST', `/api/hotels/${slug}/chat/direct/${otherUserId}`),
+    listMembers: (slug: string) =>
+      req<{ id: string; name: string; role: string }[]>('GET', `/api/hotels/${slug}/chat/members`),
     createGroup: (slug: string, name: string, memberIds: string[]) =>
       req<{ roomId: string }>('POST', `/api/hotels/${slug}/chat/group`, { name, memberIds }),
     editMessage: (slug: string, roomId: string, msgId: string, text: string) =>