commanders run on Sonnet, not the account default

every new commander came up on whatever the owner last picked in a chat —
Fable, currently. that default is chosen for interactive work, and a
commander is the opposite: long-running, mostly repeating one settled job,
and started by a button rather than by somebody thinking about which model
they want.

COMMANDER_DEFAULT_MODEL, in both places, because the two ways of starting a
commander do not share code — the server's /commanders/new route and the
detail component's own first turn.

per-surface defaults belong in settings eventually. "commanders default to
Sonnet" is the decision; this is where it lives until there is a better
place for it.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Officer-Session: 656f5c85-e49a-4f1f-b9f3-042a04b4d043

src/servers/api/command-hq/router.ts

@@ -28,7 +28,7 @@ import {
   type ChatIdentity,
   type ClaudeSessionSummary,
 } from '../chat/claude-sessions';
-import { collectRunningTasks, startClaudeTurn, getUserDefaultModel, DEFAULT_MODEL } from '../chat/websocket';
+import { collectRunningTasks, startClaudeTurn, COMMANDER_DEFAULT_MODEL } from '../chat/websocket';
 import {
   listCommandHqCategories,
   createCommandHqCategory,
@@ -373,7 +373,8 @@ commandHqRouter.post('/commanders/new', async (ctx) => {
   if (credentialError) console.warn(`[command-hq] ${row.dirName}: no credential minted — ${credentialError}`);
 
   const sessionId = randomUUID();
-  const model = (await getUserDefaultModel(user.id)) || DEFAULT_MODEL;
+  // Not the account default: a commander runs on Sonnet — see COMMANDER_DEFAULT_MODEL.
+  const model = COMMANDER_DEFAULT_MODEL;
 
   const outcome = await new Promise<{ ok: true; transcriptId: string } | { ok: false; error: string }>((resolve) => {
     // 30s covers a slow spawn (member login checks, a cold sidecar) without holding an HTTP connection