command hq: auto-name a commander from its watcher's own task description

The initial title (the mechanics preamble, truncated, when a background job is
the very first message) is expected — that's just Claude Code naming the
session from its first message, same as always. But by the time the watcher's
task actually starts, the harness has already handed it a real description
("Watch google.com reachability" for a ping watcher), and that reads far
better than the preamble ever will.

Hooked into the exact moment pendingArmWatcher is consumed — the FIRST arm,
never a self-re-arm, which the watcher-loop code already had to distinguish
for its own reasons. Resolves a fresh ChatIdentity via resolveHomeDir and
calls renameClaudeSession with msg.description. Best-effort: a failure is
logged and does not touch watcherArmed.

Known gap, noted in the doc rather than fixed: the detail panel's title bar
is fetched once on mount and won't live-refresh when this fires while it's
open. The grid's cards don't have this problem since GET /commanders already
polls every 15s.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/servers/api/chat/websocket.ts

@@ -36,6 +36,7 @@ import {
   recordCommandHqTurn,
 } from 'officerdb';
 import { resolveHomeDir } from '@@/user-home';
+import { renameClaudeSession, type ChatIdentity } from './claude-sessions';
 import { claudeLoginState } from '@@/os-user-claude';
 import { mkdirSync } from 'node:fs';
 import { logger } from './logger';
@@ -539,6 +540,39 @@ function createMessageHandler(
           void armCommandHqWatcher(userId, transcriptId, taskId).catch((err: unknown) => {
             logger.warn('Could not arm commander watcher', { sessionId, transcriptId, error: String(err) });
           });
+
+          /*
+            Auto-name the commander from the agent's own description of what it just started —
+            "Watch google.com reachability" reads better than the mechanics-preamble text every fresh
+            commander is titled with initially (expected, not a bug: that IS the first message, and
+            Claude Code names sessions from it the same way it always has). This is the one moment we
+            know for certain this is the FIRST task the watcher produced, not a self-re-arm — the
+            `else` branch below is exactly what handles every later one, and never reaches here.
+          */
+          const description = msg.description?.trim();
+          if (description) {
+            const capturedTranscriptId = transcriptId;
+            const capturedCwd = session.cwd;
+            const capturedEmail = session.email;
+            void resolveHomeDir(userId)
+              .then((resolved) => {
+                if (!resolved.ok) return;
+                const who: ChatIdentity = {
+                  email: capturedEmail,
+                  home: resolved.home,
+                  osUser: resolved.osUser,
+                  isOwner: resolved.isOwner,
+                };
+                renameClaudeSession(who, capturedCwd, capturedTranscriptId, description);
+              })
+              .catch((err: unknown) => {
+                logger.warn('Could not auto-name commander from watcher description', {
+                  sessionId,
+                  transcriptId: capturedTranscriptId,
+                  error: String(err),
+                });
+              });
+          }
         } else {
           // Not a fresh arm — but if this commander is ALREADY armed, a new task starting is exactly what
           // the agent's own self-re-arm produces (`handoffContract`: same turn, same command, new task id).