Let workers ask each other through the coordinator in chatrooms

A worker asks for another bot's help with ask_crew. The coordinator
reads the request, asks the right bot (in a workspace, only its
members), and sends the answer back into the asking bot's
conversation, waking it. Each exchange is kept as a read-only
chatroom: listed in the main rail after the workspaces, or in the
workspace's rail for requests made there, with live status rows for
each bot while it's open and a Stop button.

Room sessions are hidden from every conversation list, other bots'
words reach the model fenced as data, and turns, nesting and open
rooms are capped. Closed rooms are pruned after a retention period
and past a cap per place (Settings > General).

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

src/functions/backend/db/bot-sessions/past-session-messages-sql.test.ts

@@ -5,7 +5,7 @@ import searchPastSessionsSql, { type SearchPastSessionsParams } from "./past-ses
 /**
  * A bot's search of its earlier sessions reads only that user's
  * conversation with it (in the same place), never the session it's
- * answering. Run against real SQLite.
+ * answering, nor its part of a chatroom. Run against real SQLite.
  */
 const db = new Database(":memory:");
 
@@ -26,6 +26,12 @@ db.run(`INSERT INTO bot_messages (id, session_id, author, text) VALUES
     (6, 5, 'user', 'Acme invoice in the workspace'),
     (7, 1, 'user', 'Discount of 100% off'),
     (8, 1, 'user', 'Discount of 10 off')`);
+/**
+ * The bot's part of a chatroom: never one of its past sessions.
+ */
+db.run(`ALTER TABLE bot_sessions ADD COLUMN chatroom_id INTEGER`);
+db.run(`INSERT INTO bot_sessions (id, user_id, bot_id, workspace_id, title, chatroom_id) VALUES (6, 1, 10, NULL, 'A chatroom', 3)`);
+db.run(`INSERT INTO bot_messages (id, session_id, author, text) VALUES (9, 6, 'bot', 'Acme invoice asked in a chatroom')`);
 
 function ids(params: Partial<SearchPastSessionsParams>) {
     const { sql, values } = searchPastSessionsSql({