feat(channel): enhance message components

Update MessageItem with reactions and mentions, add PinPanel
for pinned messages, enhance ThreadPanel for threaded replies.

src/components/channel/MessageItem.tsx

@@ -21,6 +21,7 @@ interface Props {
   onSetEmojiPicker: (msgId: string | null) => void;
   onShowEditHistory: (msgId: string) => void;
   roomId: string;
+  readOnly?: boolean;
 }
 
 const COMMON_EMOJIS = ['👍', '❤️', '😄', '😭', '😡', '🎉', '🚀', '👀'];
@@ -37,14 +38,16 @@ export function MessageItem({
   onOpenThread,
   onSetEmojiPicker,
   onShowEditHistory,
+  readOnly = false,
 }: Props) {
   const [isHovered, setIsHovered] = useState(false);
   const isRevoked = !!msg.revoked;
   const { addPin, removePin, pinnedMessages } = useRoom();
   const isPinned = pinnedMessages.some((p) => p.message === msg.id);
   const handleTogglePin = () => {
-    if (isPinned) removePin(msg.id);
-    else addPin(msg.id);
+    if (readOnly) return;
+    const action = isPinned ? removePin(msg.id) : addPin(msg.id);
+    action.catch((err) => console.error('[MessageItem] failed to toggle pin:', err));
   };
   const isEdited = !!msg.edited_at;
   const isStreaming = msg.is_streaming === true;
@@ -53,6 +56,7 @@ export function MessageItem({
 
   return (
     <div
+      data-message-id={msg.id}
       style={{
         position: 'relative',
         padding: isCompact ? '1px 16px 1px' : '4px 16px 4px',
@@ -160,7 +164,7 @@ export function MessageItem({
               {reactions.map((reaction) => (
                 <button
                   key={reaction.emoji}
-                  onClick={() => onReaction(msg.id, reaction.emoji)}
+                  onClick={readOnly ? undefined : () => onReaction(msg.id, reaction.emoji)}
                   style={{
                     display: 'flex',
                     alignItems: 'center',
@@ -169,7 +173,7 @@ export function MessageItem({
                     background: reaction.reacted_by_me ? 'var(--accent-muted)' : 'var(--surface-elevated)',
                     border: `1px solid ${reaction.reacted_by_me ? 'var(--accent)' : 'transparent'}`,
                     borderRadius: 12,
-                    cursor: 'pointer',
+                    cursor: readOnly ? 'default' : 'pointer',
                     fontSize: 13,
                     transition: 'all 0.1s',
                   }}
@@ -179,13 +183,13 @@ export function MessageItem({
                 </button>
               ))}
               <button
-                onClick={() => onSetEmojiPicker(showPicker ? null : msg.id)}
+                onClick={readOnly ? undefined : () => onSetEmojiPicker(showPicker ? null : msg.id)}
                 style={{
                   padding: '2px 6px',
                   background: 'transparent',
                   border: '1px dashed var(--border-default)',
                   borderRadius: 12,
-                  cursor: 'pointer',
+                  cursor: readOnly ? 'default' : 'pointer',
                   color: 'var(--text-muted)',
                   fontSize: 13,
                 }}
@@ -230,7 +234,7 @@ export function MessageItem({
           )}
 
           {/* Thread badge */}
-          {msg.thread && (
+          {msg.thread && !readOnly && (
             <button
               onClick={() => onOpenThread(msg)}
               style={{
@@ -254,7 +258,7 @@ export function MessageItem({
       </div>
 
       {/* Hover actions — Discord-style: button center aligns with message top edge */}
-      {isHovered && !isRevoked && (
+      {isHovered && !isRevoked && !readOnly && (
         <div
           style={{
             position: 'absolute',
@@ -285,6 +289,13 @@ export function MessageItem({
           >
             <Reply className="w-3 h-3" />
           </button>
+          <button
+            onClick={() => onOpenThread(msg)}
+            title={msg.thread ? 'Open thread' : 'Start thread'}
+            className={MESSAGE_ITEM.actionButton}
+          >
+            <MessageSquare className="w-3 h-3" />
+          </button>
           {msg.sender_type !== 'ai' && (
             <>
               <button
@@ -302,6 +313,8 @@ export function MessageItem({
               >
                 <Trash2 className="w-3 h-3" />
               </button>
+            </>
+          )}
           <button
             onClick={handleTogglePin}
             title={isPinned ? 'Unpin' : 'Pin'}
@@ -310,8 +323,6 @@ export function MessageItem({
           >
             <Pin className="w-3 h-3" />
           </button>
-            </>
-          )}
         </div>
       )}
     </div>

src/components/channel/MessageList.tsx

@@ -41,6 +41,7 @@ interface Props {
   onShowEditHistory: (msgId: string) => void;
   onStartReached?: () => void;
   roomId: string;
+  readOnly?: boolean;
 }
 
 export function MessageList({
@@ -57,6 +58,7 @@ export function MessageList({
   onShowEditHistory,
   onStartReached,
   roomId,
+  readOnly = false,
 }: Props) {
   const virtuosoRef = useRef<VirtuosoHandle>(null);
   const initialScrollDoneRef = useRef(false);
@@ -208,6 +210,7 @@ export function MessageList({
               onSetEmojiPicker={onSetEmojiPicker}
               onShowEditHistory={onShowEditHistory}
               roomId={roomId}
+              readOnly={readOnly}
             />
           );
         }}

src/components/channel/PinPanel.tsx

@@ -1,14 +1,18 @@
-import { Pin, X } from 'lucide-react';
-import type { PinnedMessage } from '@/contexts/room';
+import { Pin, PinOff, X } from 'lucide-react';
+import type { Message, PinnedMessage } from '@/contexts/room';
 import { formatRelativeTime } from '@/contexts/room';
 
 interface Props {
   pins: PinnedMessage[];
+  messages: Message[];
   onClose: () => void;
   onGotoMessage: (messageId: string) => void;
+  onUnpin?: (messageId: string) => void;
 }
 
-export function PinPanel({ pins, onClose, onGotoMessage }: Props) {
+export function PinPanel({ pins, messages, onClose, onGotoMessage, onUnpin }: Props) {
+  const messageById = new Map(messages.map((msg) => [msg.id, msg]));
+
   return (
     <div className="pin-panel">
       <div className="pin-panel-header">
@@ -28,21 +32,58 @@ export function PinPanel({ pins, onClose, onGotoMessage }: Props) {
             No pinned messages yet.
           </div>
         ) : (
-          pins.map((pin) => (
+          pins.map((pin) => {
+            const msg = messageById.get(pin.message);
+            return (
+              <div key={pin.message} className="pin-item" style={{ alignItems: 'flex-start', gap: 8 }}>
                 <button
-              key={pin.message}
-              className="pin-item"
                   onClick={() => onGotoMessage(pin.message)}
+                  style={{
+                    flex: 1,
+                    minWidth: 0,
+                    display: 'flex',
+                    flexDirection: 'column',
+                    gap: 4,
+                    background: 'none',
+                    border: 'none',
+                    padding: 0,
+                    textAlign: 'left',
+                    cursor: 'pointer',
+                  }}
                 >
-              <Pin className="w-3 h-3" style={{ color: 'var(--text-muted)', flexShrink: 0 }} />
-              <span style={{ color: 'var(--text-muted)', fontSize: 12 }}>
-                #{pin.message.slice(0, 8)}
+                  <span style={{ color: 'var(--text-primary)', fontSize: 13, fontWeight: 600 }}>
+                    {msg?.display_name ?? msg?.sender_id ?? `#${pin.message.slice(0, 8)}`}
                   </span>
-              <span style={{ color: 'var(--text-muted)', fontSize: 11, marginLeft: 'auto' }}>
-                {formatRelativeTime(pin.pinned_at)}
+                  <span
+                    style={{
+                      color: msg ? 'var(--text-secondary)' : 'var(--text-muted)',
+                      fontSize: 12,
+                      lineHeight: 1.4,
+                      overflow: 'hidden',
+                      display: '-webkit-box',
+                      WebkitLineClamp: 3,
+                      WebkitBoxOrient: 'vertical',
+                    }}
+                  >
+                    {msg?.content ?? 'Pinned message is not loaded in the current history window.'}
+                  </span>
+                  <span style={{ color: 'var(--text-muted)', fontSize: 11 }}>
+                    Pinned {formatRelativeTime(pin.pinned_at)}
                   </span>
                 </button>
-          ))
+                {onUnpin && (
+                  <button
+                    onClick={() => onUnpin(pin.message)}
+                    title="Unpin"
+                    className="thread-close-btn"
+                    style={{ flexShrink: 0 }}
+                  >
+                    <PinOff className="w-3 h-3" style={{ color: 'var(--text-muted)' }} />
+                  </button>
+                )}
+              </div>
+            );
+          })
         )}
       </div>
     </div>

src/components/channel/ThreadPanel.tsx

@@ -5,6 +5,9 @@ import type { Message } from '@/contexts/room';
 import { formatTime } from '@/contexts/room';
 import { Avatar } from './Avatar';
 import { getWsClient } from '@/ws';
+import { ProjectJoinBanner } from '@/app/project/layout';
+import { IrRenderer } from '@/lib/ir/renderer';
+import { extractIrNodes } from '@/lib/ir/parser';
 
 function safeGetClient() {
   try { return getWsClient(); } catch { return null; }
@@ -21,6 +24,7 @@ interface Props {
   sendMessage: (content: string, opts?: { thread?: string }) => void;
   onTypingStart: () => void;
   onTypingStop: () => void;
+  readOnly?: boolean;
 }
 
 const COMMON_EMOJIS = ['👍', '❤️', '😄', '😭', '😡', '🎉'];
@@ -32,6 +36,7 @@ export function ThreadPanel({
   sendMessage,
   onTypingStart,
   onTypingStop,
+  readOnly = false,
 }: Props) {
   const [inputValue, setInputValue] = useState('');
   const [showReactionPicker, setShowReactionPicker] = useState<string | null>(null);
@@ -43,7 +48,7 @@ export function ThreadPanel({
   }, [thread.messages]);
 
   const handleSend = () => {
-    if (!inputValue.trim()) return;
+    if (readOnly || !inputValue.trim()) return;
     sendMessage(inputValue.trim(), { thread: thread.id });
     setInputValue('');
     onTypingStop();
@@ -51,6 +56,7 @@ export function ThreadPanel({
   };
 
   const handleInputChange = (e: React.ChangeEvent<HTMLTextAreaElement>) => {
+    if (readOnly) return;
     setInputValue(e.target.value);
     if (typingTimeoutRef.current) clearTimeout(typingTimeoutRef.current);
     onTypingStart();
@@ -58,11 +64,13 @@ export function ThreadPanel({
   };
 
   const handleResolve = () => {
+    if (readOnly) return;
     const c = safeGetClient();
     if (c) c.resolveThread(thread.id);
   };
 
   const handleArchive = () => {
+    if (readOnly) return;
     const c = safeGetClient();
     if (c) c.archiveThread(thread.id);
   };
@@ -118,7 +126,7 @@ export function ThreadPanel({
                   {isRevoked ? (
                     <span style={{ color: 'var(--text-muted)', fontStyle: 'italic' }}>Message deleted</span>
                   ) : (
-                    msg.content
+                    <IrRenderer nodes={extractIrNodes(msg.content)} />
                   )}
                 </div>
               </div>
@@ -136,6 +144,11 @@ export function ThreadPanel({
         </div>
       )}
 
+      {readOnly ? (
+        <div className="thread-input-area">
+          <ProjectJoinBanner compact message="Join this project to reply in threads." />
+        </div>
+      ) : (
       <div className="thread-input-area">
         <button
           className="thread-reaction-btn"
@@ -164,6 +177,7 @@ export function ThreadPanel({
           <Send className="w-4 h-4" />
         </button>
       </div>
+      )}
     </div>
   );
 }