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/utils/take-over-ref.ts

@@ -0,0 +1,15 @@
+import type { ComputerViewMode } from "@/src/dict/computer-dict";
+
+type Params = {
+    id: number | string;
+    mode: ComputerViewMode;
+};
+
+/**
+ * How a bot asks the user to take over one of its computers in a message:
+ * `[take-over:3:browser]`. The chat shows it as a button that opens the
+ * computer in that mode.
+ */
+export default function takeOverRef({ id, mode }: Params) {
+    return `[take-over:${id}:${mode}]`;
+}