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]/(data)/bot-computers-context.ts

@@ -2,10 +2,12 @@ import React from "react";
 import type { BotComputers } from "../(hooks)/use-bot-computers";
 
 /**
- * The open bot's computers and the switch, shared by the header's
- * computer select and the computer buttons in its messages.
+ * The open bot's computers, the switch and the viewer, shared by the
+ * header's computers modal and the computer buttons in its messages.
  */
 export const BotComputersContext = React.createContext<BotComputers>({
     computers: [],
     switchComputer: async () => {},
+    openComputer: () => {},
+    closeComputer: () => {},
 });