fix(paired): auto-provision paired workspace so tribunal rooms get a reviewer on registration

Rooms registered as tribunal had no work_dir and no paired_projects row, so
ensurePairedProject() returned null, no paired task was ever created, and only
the owner ran — the reviewer/arbiter never fired (web-vstock and 4 other rooms).

Add ensurePairedWorkspaceProvisioned(): defaults canonical work_dir to
groups/<folder>, guarantees it is a standalone git repo with an initial commit
(detected via a LOCAL .git so we never walk up into the EJClaw checkout and
create a stray worktree), and upserts the paired_projects row. Wire it into
setup/register.ts so every newly registered room is immediately usable by the
full owner→reviewer→arbiter flow. Adds a regression test.

setup/register.ts

@@ -9,6 +9,7 @@ import path from 'path';
 import { GROUPS_DIR } from '../src/config.js';
 import { assignRoom, initDatabase } from '../src/db.js';
 import { isValidGroupFolder } from '../src/group-folder.js';
+import { ensurePairedWorkspaceProvisioned } from '../src/paired-workspace-manager.js';
 import { logger } from '../src/logger.js';
 import { emitStatus } from './status.js';
 
@@ -109,6 +110,24 @@ export async function run(args: string[]): Promise<void> {
   });
   logger.info('Assigned room through canonical room service');
 
+  // Provision the paired workspace so a tribunal room's reviewer/arbiter work
+  // immediately on registration. Without this the room has work_dir=null and
+  // the paired flow never creates a task, so only the owner ever runs.
+  const canonicalWorkDir = ensurePairedWorkspaceProvisioned({
+    chatJid: parsed.jid,
+    groupFolder: parsed.folder,
+  });
+  assignRoom(parsed.jid, {
+    name: parsed.name,
+    folder: parsed.folder,
+    isMain: parsed.isMain,
+    workDir: canonicalWorkDir,
+  });
+  logger.info(
+    { folder: parsed.folder, canonicalWorkDir },
+    'Provisioned paired workspace for room so reviewer/arbiter run on registration',
+  );
+
   fs.mkdirSync(path.join(GROUPS_DIR, parsed.folder, 'logs'), {
     recursive: true,
   });