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/utils/message-preview.test.ts

@@ -0,0 +1,20 @@
+import { describe, expect, test } from "bun:test";
+import messagePreview from "./message-preview";
+
+describe("messagePreview", () => {
+    test("strips markdown and names computers plainly", () => {
+        expect(
+            messagePreview({
+                text: "## Found it\n\nYour **GitHub** session is on [computer:3]. See [the docs](https://x.y) and `search_computers`.\n\n- *one*\n- two",
+            }),
+        ).toBe("Found it Your GitHub session is on a computer. See the docs and search_computers. one two");
+    });
+
+    test("keeps code text without its fences", () => {
+        expect(messagePreview({ text: "Run:\n```bash\nls ~\n```" })).toBe("Run: ls ~");
+    });
+
+    test("leaves plain text alone", () => {
+        expect(messagePreview({ text: "All done, 3 files_moved." })).toBe("All done, 3 files_moved.");
+    });
+});