Open computers from the chat, let bots ask for a take-over, show task progress

- Serve each computer to its owner under /computers/<id>/ (HTTP and
  websockets proxied to the AIO sandbox) and show it in a shared
  ComputerView with browser, terminal and code modes, opened from the
  computers modal or a take-over button in the thread.
- ask_user_to_take_over lets a bot hand a computer to the user for a
  login or captcha; the message gets a take-over button and needs-you,
  and the viewer hands it back with a chat message.
- While a task runs the thread shows "<bot> is working..." with the
  task's latest step; steps read as plain words, not tool names.
- A coordinator with no workers no longer claims to delegate, and bots
  describe started tasks in the first person.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/pages/admin/bots/[bot_id]/(partials)/message-thread.tsx

@@ -7,14 +7,19 @@ import MessageGroupBlock from "./message-group-block";
 type Props = {
     bot: BotWithLastMessage;
     messages: BotMessageWithAttachments[];
+    /**
+     * The latest step of the bot's active task, shown while it works.
+     */
+    progress?: string | null;
 };
 
 /**
  * Bottom-anchored: the stack sits 24px above the composer rule and grows
  * upward. Empty space belongs at the top. New messages announce politely.
- * While the bot works on a reply, a thinking row sits under the last one.
+ * While the bot works on a reply or a task, a status row sits under the
+ * last one.
  */
-export default function MessageThread({ bot, messages }: Props) {
+export default function MessageThread({ bot, messages, progress }: Props) {
     const groups = groupMessages({ messages });
 
     return (
@@ -28,7 +33,7 @@ export default function MessageThread({ bot, messages }: Props) {
                 {groups.map((group) => (
                     <MessageGroupBlock key={group.key} bot={bot} group={group} />
                 ))}
-                <BotThinkingRow bot={bot} />
+                <BotThinkingRow bot={bot} progress={progress} />
             </Stack>
         </Stack>
     );