feat(frontend): hide channel-members section for public channels

Public channel selected -> single guild member list (no In-channel split).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/pages/ChatPage.tsx

@@ -33,7 +33,7 @@ function timeOf(iso?: string): string {
 const X_TYPES = ['general', 'work', 'report', 'discuss', 'triage', 'custom'] as const
 type XType = (typeof X_TYPES)[number]
 
-type GuildChannel = { id: string; name: string; guildId?: string; xType?: XType; isMember?: boolean }
+type GuildChannel = { id: string; name: string; guildId?: string; xType?: XType; isMember?: boolean; isPublic?: boolean }
 type MemberItem = { userId: string; email: string; name: string; status: string }
 
 export default function ChatPage() {
@@ -514,7 +514,7 @@ export default function ChatPage() {
 
       {showMembers ? (
         <aside className="dc-members">
-          {currentChannel ? (
+          {currentChannel && !currentChannel.isPublic ? (
             <>
               <div className="dc-section-label">
                 <span>In channel — {channelMembers.length}</span>