Add cac-litespeed image family (OpenLiteSpeed, native LSAPI)

New paid-tier per-customer image built on litespeedtech/openlitespeed:1.8.4-lsphpNN.
Matrix: 8.1-8.5. Native LSAPI suexec to customer uid, server-level LSCache,
all WP/WooCommerce extensions (memcached, redis, imagick, mbstring, etc.) baked in.

Files:
- Dockerfile.litespeed (FROM prebuilt LiteSpeed base, layers wp-cli/composer/mariadb)
- configs/litespeed/{httpd_config,site-template,lsphp-overrides}.tpl
- scripts/{entrypoint,create-vhost,detect-memory}-litespeed.sh + install-lscache-wp.sh

CI: new Build-LiteSpeed-Images matrix job. OLS_VERSION pinned to 1.8.4 (only
release with prebuilt images for all 5 PHP versions on Docker Hub).

Spec: whp/docs/superpowers/specs/2026-06-01-cac-litespeed-design.md

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

configs/litespeed/lsphp-overrides.ini

@@ -0,0 +1,43 @@
+; Production lsphp overrides — mirrors configs/prod-php.ini for the FPM
+; image, adapted for LSAPI defaults. Dropped into /usr/local/lsws/lsphpNN/etc/php.d/
+
+memory_limit = 256M
+post_max_size = 384M
+upload_max_filesize = 256M
+max_input_vars = 2000
+max_execution_time = 60
+max_input_time = 120
+
+expose_php = Off
+short_open_tag = Off
+
+display_errors = Off
+log_errors = On
+error_reporting = E_ALL & ~E_DEPRECATED & ~E_STRICT
+zend.exception_ignore_args = On
+
+session.save_handler = files
+session.use_cookies = 1
+session.use_only_cookies = 1
+session.use_strict_mode = 0
+session.gc_probability = 1
+session.gc_divisor = 1000
+session.gc_maxlifetime = 1440
+
+opcache.enable = 1
+opcache.memory_consumption = 128
+opcache.interned_strings_buffer = 8
+opcache.max_accelerated_files = 10000
+opcache.revalidate_freq = 60
+opcache.enable_cli = Off
+
+output_buffering = 4096
+default_charset = "UTF-8"
+
+file_uploads = On
+max_file_uploads = 20
+
+soap.wsdl_cache_enabled = 1
+soap.wsdl_cache_dir = "/tmp"
+soap.wsdl_cache_ttl = 86400
+soap.wsdl_cache_limit = 5