Add computer switching, crew reporting, job steps and markdown chat

- Bots have a current computer (bots.computer_id), switched from the chat
  header beside the model button or by clicking a computer the bot names
  ([computer:ID]); tasks run on it by default
- search_computers runs one read-only command on all of a bot's computers;
  chat replies know their computers (compose-computers-note)
- The coordinator can use every computer and grants or revokes crew access
  with assign_computer
- Delegated jobs record requested_by_bot_id; the worker's result or failure
  is reported back in the coordinator's conversation
- bots_queue_updates records each model turn of a job, pushed live and shown
  in the working-on panel
- Live relay: every process pushes new messages, job steps and bot changes
  from the database to its own sockets, so work done elsewhere shows live
- Bot messages render as markdown (react-markdown + remark-gfm, no raw HTML)
  with twui components; rail previews are plain text
- Fix header button overflow in the model and computer selects
- Bump @moduletrace/twui to 0.1.2

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

src/data/harness-prompts.ts

@@ -32,7 +32,7 @@ You are chatting with the user. Answer their latest messages directly and briefl
 /**
  * Added to the coordinator's chat prompt: it hands work to the crew.
  */
-export const CoordinatorReplyNote = `As the coordinator, hand work that fits a crew member's role to them with delegate_task. They post the result in their own conversation, so tell the user who is on it.`;
+export const CoordinatorReplyNote = `As the coordinator, hand work that fits a crew member's role to them with delegate_task. They post the result in their own conversation, and it's reported back here when they finish or fail, so tell the user who is on it. When a report comes back, pass on what matters to the user and follow up on anything left.`;
 
 /**
  * Added to a bot's prompt when it works through a queued task.