feat(setup): clarify setup flow from user-feedback session

- Container step: duration hint + 3-line rolling output window with
  60s stall detector that offers "keep waiting" vs "ask Claude"
- First chat: reframed as a try-out with sandbox-model explainer
  (wakes on message, sleeps when idle, context persists)
- Timezone: auto-detected non-UTC zones now get an explicit
  confirm from the user instead of silent persist
- Outro: added always-on warning + prominent "check your DM" banner
  when a channel was configured; directive last line
- Discord: always show token-location reminder even when user says
  they have one; new "do you have a server?" branch walks through
  server creation if not
- All select prompts: custom brightSelect renderer keeps inactive
  option labels at full brightness (was dim gray); adds @clack/core
  as a direct dep

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

setup/container.ts

@@ -174,19 +174,31 @@ export async function run(args: string[]): Promise<void> {
     // .env is optional; absence is normal on a fresh checkout
   }
 
-  // Build
+  // Build — stdio inherit so the parent setup runner can tail docker's
+  // per-step output and render it in a rolling window. Previously we used
+  // execSync which buffered everything; users couldn't tell whether a
+  // 3–10 minute build was making progress or hung.
   let buildOk = false;
   log.info('Building container', { runtime, buildArgs });
-  try {
-    const argsStr = buildArgs.length > 0 ? ' ' + buildArgs.join(' ') : '';
-    execSync(`${buildCmd}${argsStr} -t ${image} .`, {
+  const buildRes = spawnSync(
+    buildCmd.split(' ')[0],
+    [
+      ...buildCmd.split(' ').slice(1),
+      ...buildArgs.flatMap((a) => a.split(' ')),
+      '-t',
+      image,
+      '.',
+    ],
+    {
       cwd: path.join(projectRoot, 'container'),
-      stdio: ['ignore', 'pipe', 'pipe'],
-    });
+      stdio: 'inherit',
+    },
+  );
+  if (buildRes.status === 0) {
     buildOk = true;
     log.info('Container build succeeded');
-  } catch (err) {
-    log.error('Container build failed', { err });
+  } else {
+    log.error('Container build failed', { exitCode: buildRes.status });
   }
 
   // Test