Use proxy_block placeholder in vhost template for FPM load balancing

Replaced hardcoded SetHandler + ProxyFCGISetEnvIf directives with a
~~proxy_block~~ placeholder. The shared_httpd_manager generates either
a direct SetHandler (single container) or a mod_proxy_balancer config
(multiple containers) depending on the site's container count.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

configs/shared-vhost-template.tpl

@@ -27,17 +27,7 @@
     SSLCertificateFile /etc/pki/tls/certs/localhost.crt
     SSLCertificateKeyFile /etc/pki/tls/private/localhost.key
 
-    <FilesMatch \.php$>
+    ~~proxy_block~~
-        SetHandler "proxy:fcgi://~~fpm_host~~:~~fpm_port~~"
-    </FilesMatch>
-
-    # The shared httpd serves files from /mnt/users/{user}/{domain}/public_html
-    # but the FPM container has them at /home/{user}/public_html.
-    # Override both DOCUMENT_ROOT and SCRIPT_FILENAME so PHP sees the
-    # correct paths (required for plugins like WordFence that use
-    # $_SERVER['DOCUMENT_ROOT'] to locate config files).
-    ProxyFCGISetEnvIf "true" DOCUMENT_ROOT "/home/~~user~~/public_html"
-    ProxyFCGISetEnvIf "true" SCRIPT_FILENAME "/home/~~user~~/public_html%{reqenv:SCRIPT_NAME}"
 
     DirectoryIndex index.php index.html index.htm