fix(shared-ols): enableCache 0 so headerless responses are never cached

LSCWP's Divi compat disables the plugin for ?et_fb= / ?et_pb_preview= /
?preview=true, so those responses carry no X-LiteSpeed-Cache-Control header.
With module-level enableCache 1, OLS cached them anyway (Divi Visual Builder
pages served from cache; the plugin's own QS exclusion never runs).

enableCache 0 caches only responses that opt in via an explicit
X-LiteSpeed-Cache-Control: public header. Measured on OLS 1.8.4: headerless
= miss,hit under 1 / not cached under 0; explicit public cached under both.
Matches the dedicated cac-litespeed tier.

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

configs/shared-ols/httpd_config_base.tpl

@@ -23,10 +23,22 @@ useIpInProxyHeader        1
 
 ## LSCache enabled at MODULE scope for the whole tier (dedicated cache volume,
 ## ephemeral across rebuilds; OLS auto-keys a per-vhost subdir under storagePath).
-## PUBLIC (anonymous) caching ONLY: enableCache 1 + checkPublicCache 1 let OLS
+## PUBLIC (anonymous) caching ONLY: checkPublicCache 1 lets OLS serve cacheable,
-## serve cacheable, non-logged-in responses marked by the LiteSpeed Cache WP
+## non-logged-in responses that are EXPLICITLY marked by the LiteSpeed Cache WP
 ## plugin's X-LiteSpeed-Cache-Control headers (ignoreRespCacheCtrl=0 honors them).
 ##
+## enableCache is 0 ON PURPOSE. At module scope enableCache 1 means "cache every
+## cacheable-looking public response by default", INCLUDING ones that carry no
+## cache header at all. That bit us on Divi: LSCWP's Divi compat calls
+## litespeed_disable_all for ?et_fb= / ?et_pb_preview= / ?p=N&preview=true, which
+## switches the plugin off for the request, so it sends NO header (and its own
+## "Do Not Cache Query Strings" never runs) — and OLS stored the Visual Builder
+## page under enableCache 1. With enableCache 0 only responses that opt in via
+## X-LiteSpeed-Cache-Control: public are stored; a plugin-disabled request is
+## simply not cached. Measured on OLS 1.8.4 (2026-09-21): headerless response =
+## miss,hit under 1; not cached under 0; explicit `public` header cached under
+## both. Matches the dedicated cac-litespeed tier (configs/litespeed/site-template.tpl).
+##
 ## PRIVATE caching is intentionally OFF (enablePrivateCache 0 + checkPrivateCache 0).
 ## Logged-in / cookie-bearing pages must NEVER be cached at the tier. We previously
 ## left enablePrivateCache=1 assuming "no plugin -> nothing cached," but that was
@@ -45,7 +57,7 @@ module cache {
   respCookieCache         1
   ignoreReqCacheCtrl      0
   ignoreRespCacheCtrl     0
-  enableCache             1
+  enableCache             0
   enablePrivateCache      0
 }
 ## ---- end shared-ols server append ----