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.ts

@@ -0,0 +1,17 @@
+/**
+ * A bot message as one line of plain text, for the rail's preview: no
+ * markdown syntax, links as their text, computer refs (`computerRef`) as
+ * "a computer", whitespace collapsed.
+ */
+export default function messagePreview({ text }: { text: string }) {
+    return text
+        .replace(/```[^\n]*\n?/g, "")
+        .replace(/\[computer:\d+\](?!\()/g, "a computer")
+        .replace(/!?\[([^\]]*)\]\([^)]*\)/g, "$1")
+        .replace(/^\s{0,3}(#{1,6}\s+|>\s?|[-*+]\s+|\d+\.\s+)/gm, "")
+        .replace(/(\*\*|__|~~|`)/g, "")
+        .replace(/(^|\s)[*_](\S[^*_]*\S|\S)[*_](?=\s|$|[.,;:!?])/g, "$1$2")
+        .replace(/\|/g, " ")
+        .replace(/\s+/g, " ")
+        .trim();
+}