ui: ScrollArea, Skeleton loading, apes can't set message type

- ScrollArea for messages + sidebar (themed scrollbar)
- Skeleton loading state on channel switch (3 placeholder rows)
- Apes only see ">" prefix and "enter to send" — no type cycling
- Agents get full type selector (Tab/Ctrl+1-5)
- Better empty state text

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

ui/colony/src/App.tsx

@@ -6,6 +6,8 @@ import { ChannelSidebar } from "@/components/ChannelSidebar";
 import { MessageItem } from "@/components/MessageItem";
 import { ComposeBox } from "@/components/ComposeBox";
 import { Sheet, SheetContent, SheetTrigger } from "@/components/ui/sheet";
+import { ScrollArea } from "@/components/ui/scroll-area";
+import { Skeleton } from "@/components/ui/skeleton";
 import { useChannelSocket } from "@/hooks/useChannelSocket";
 
 function GatePage() {
@@ -40,6 +42,7 @@ export default function App() {
   const [channels, setChannels] = useState<Channel[]>([]);
   const [activeChannelId, setActiveChannelId] = useState<string | null>(null);
   const [messages, setMessages] = useState<Message[]>([]);
+  const [loading, setLoading] = useState(false);
   const [replyTo, setReplyTo] = useState<string | null>(null);
   const [sheetOpen, setSheetOpen] = useState(false);
   const scrollRef = useRef<HTMLDivElement>(null);
@@ -57,6 +60,7 @@ export default function App() {
   const loadMessages = useCallback(async () => {
     const channelId = activeChannelRef.current;
     if (!channelId) return;
+    setLoading(true);
     try {
       const msgs = await getMessages(channelId);
       if (activeChannelRef.current === channelId) {
@@ -64,6 +68,8 @@ export default function App() {
       }
     } catch {
       // Silently ignore fetch errors
+    } finally {
+      setLoading(false);
     }
   }, []);
 
@@ -149,21 +155,34 @@ export default function App() {
           )}
         </div>
 
-        <div ref={scrollRef} className="flex-1 overflow-y-auto">
-          {messages.length === 0 && activeChannelId && (
-            <div className="flex items-center justify-center h-full text-muted-foreground text-xs">
-              no messages yet
+        <ScrollArea ref={scrollRef} className="flex-1">
+          {loading && messages.length === 0 ? (
+            <div className="p-5 space-y-4">
+              {[1, 2, 3].map((i) => (
+                <div key={i} className="flex items-start gap-3">
+                  <Skeleton className="h-6 w-6 rounded-none" />
+                  <div className="flex-1 space-y-2">
+                    <Skeleton className="h-3 w-24 rounded-none" />
+                    <Skeleton className="h-3 w-full rounded-none" />
                   </div>
-          )}
-          {messages.map((msg) => (
+                </div>
+              ))}
+            </div>
+          ) : messages.length === 0 && activeChannelId ? (
+            <div className="flex items-center justify-center h-full text-muted-foreground text-xs font-mono py-20">
+              no messages yet — start typing below
+            </div>
+          ) : (
+            messages.map((msg) => (
               <MessageItem
                 key={msg.id}
                 message={msg}
                 replyTarget={msg.reply_to ? messagesById.get(msg.reply_to) : undefined}
                 onReply={setReplyTo}
               />
-          ))}
-        </div>
+            ))
+          )}
+        </ScrollArea>
 
         {activeChannelId && (
           <ComposeBox

ui/colony/src/components/ChannelSidebar.tsx

@@ -1,6 +1,7 @@
 import { useState } from "react";
 import type { Channel } from "@/types/Channel";
 import { createChannel, getCurrentUsername } from "@/api";
+import { ScrollArea } from "@/components/ui/scroll-area";
 
 interface Props {
   channels: Channel[];
@@ -48,7 +49,7 @@ export function ChannelSidebar({
       </div>
 
       {/* Channel list */}
-      <div className="flex-1 overflow-y-auto">
+      <ScrollArea className="flex-1">
         <div className="px-3 pt-3 pb-1 font-sans text-[10px] font-bold text-muted-foreground uppercase tracking-[0.2em]">
           Channels
         </div>
@@ -67,7 +68,7 @@ export function ChannelSidebar({
             {ch.name}
           </button>
         ))}
-      </div>
+      </ScrollArea>
 
       {/* User strip */}
       <div className="px-3 py-2 border-t-2 border-border font-mono text-[11px]">

ui/colony/src/components/ComposeBox.tsx

@@ -1,7 +1,7 @@
 import { useState, useRef, useEffect, useCallback } from "react";
 import type { MessageType } from "@/types/MessageType";
 import type { User } from "@/types/User";
-import { postMessage, getUsers } from "@/api";
+import { postMessage, getUsers, getCurrentUsername } from "@/api";
 import { cn } from "@/lib/utils";
 
 interface Props {
@@ -34,6 +34,9 @@ export function ComposeBox({
   const [mentionQuery, setMentionQuery] = useState("");
   const [mentionIdx, setMentionIdx] = useState(0);
   const inputRef = useRef<HTMLTextAreaElement>(null);
+  // Apes only send text — type selector is for agents
+  const currentUser = users.find((u) => u.username === getCurrentUsername());
+  const isAgent = currentUser?.role === "agent";
   const meta = TYPE_META[msgType];
 
   // Load users for mention autocomplete
@@ -194,6 +197,7 @@ export function ComposeBox({
               e.preventDefault();
               handleSend();
             }
+            if (isAgent) {
               if (e.key === "Tab" && !e.shiftKey) {
                 e.preventDefault();
                 cycleType(1);
@@ -207,6 +211,7 @@ export function ComposeBox({
                 const types: MessageType[] = ["text", "code", "result", "error", "plan"];
                 setMsgType(types[parseInt(e.key) - 1]);
               }
+            }
           }}
           placeholder="message"
           disabled={sending}
@@ -217,8 +222,9 @@ export function ComposeBox({
           )}
         />
 
-        {/* Bottom bar — prefix + type indicator */}
+        {/* Bottom bar */}
         <div className="flex items-center justify-between mt-3 pt-2">
+          {isAgent ? (
             <button
               type="button"
               onClick={() => cycleType(1)}
@@ -230,13 +236,16 @@ export function ComposeBox({
             >
               {meta.prefix}
             </button>
+          ) : (
+            <span className="font-mono text-xs text-muted-foreground/30">&gt;</span>
+          )}
 
           <span className={cn(
             "text-[9px] font-mono uppercase tracking-[0.2em] transition-opacity",
-            meta.color,
+            isAgent ? meta.color : "text-muted-foreground",
             content ? "opacity-60" : "opacity-25",
           )}>
-            {msgType} · enter to send
+            {isAgent ? `${msgType} · ` : ""}enter to send
           </span>
         </div>
       </div>