fix(cli): bump default enable-ssh --full-config command delay to 5s

Follow-up to the 3s default from earlier in #515: the reporter agreed
5s is a better trade-off (issue comment 5230881285) — more headroom
than the original guess, still comfortably under the ~7s gap their
manual A/B test used.

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

pkg/service/setup/enable_ssh.go

@@ -41,11 +41,12 @@ func (m *Manager) ResetBoseURLs(deviceIP, serviceURL string) (string, error) {
 // device (#515, issue comment 5228449448): the same six commands sent
 // back-to-back left sshd down after reboot, but succeeded when sent one at a
 // time with ~7s gaps — sending fast enough may not let the device fully
-// process one command before the next arrives. 3s is a reasonable middle
-// ground (the reporter didn't try to find the true minimum); the caller
-// exposes it as a flag so a specific device can be tuned without a code
-// change.
-const DefaultTelnetCommandDelay = 3 * time.Second
+// process one command before the next arrives. Settled on 5s as the default
+// (issue comment 5230881285): a bit more headroom than the original 3s
+// guess, still well under the ~7s the reporter used without having tried to
+// find the true minimum; the caller exposes it as a flag so a specific
+// device can be tuned without a code change.
+const DefaultTelnetCommandDelay = 5 * time.Second
 
 // EnableSSHViaTelnetFullConfig is the #515 variant of EnableSSHViaTelnet for
 // devices where the single-envswitch injection is accepted and persisted but