fix(cli): correct misleading comment on isPortAvailable IPv6 coverage

The comment claimed connect-based detection works for IPv6 listeners,
but the probe only connects to 127.0.0.1 (IPv4). Updated the comment
to accurately document this limitation.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/cli/src/lib/web-dir.ts

@@ -17,13 +17,13 @@ const require = createRequire(import.meta.url);
 const DEFAULT_TERMINAL_PORT = 14800;
 
 /**
- * Check if a TCP port is available by attempting to connect to it.
+ * Check if a TCP port is available by attempting to connect to it on IPv4.
  * A successful connect means something is already listening (port in use).
  * ECONNREFUSED means nothing is listening (port free).
  *
- * Connect-based detection is more reliable than bind-based because it works
- * regardless of whether the occupying process is bound to 127.0.0.1, ::1,
- * 0.0.0.0, or :: (IPv6 wildcard).
+ * Note: Only probes 127.0.0.1 (IPv4). Processes listening exclusively on
+ * IPv6 (::1 with IPV6_V6ONLY=1) will not be detected — this is acceptable
+ * since the dashboard binds to 0.0.0.0 by default.
  */
 export function isPortAvailable(port: number): Promise<boolean> {
   return new Promise((resolve) => {