feat(installer): default -install to y

Running without parameters previously skipped package install and
failed at certbot on a clean server. Packages now install by default;
use -install n to skip.

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

x-ui-latest.sh

@@ -58,7 +58,7 @@ FAKE_SITE_COUNT=50
 domain=""
 reality_domain=""
 UNINSTALL="x"
-INSTALL="n"
+INSTALL="y"
 AUTODOMAIN="n"
 CFALLOW="n"