feat(cache): WP Fastest Cache statt WP Super Cache

Die Cache-Integration war für WP Super Cache gebaut, eingesetzt wird aber
WP Fastest Cache. Profil (wpfc), Listener, Drosselung, lit/cache-clear und
Leeren-Probe laufen jetzt über die öffentlichen WPFC-Funktionen
wpfc_clear_post_cache_by_id/wpfc_clear_all_cache; die Probe leert nur die
Wegwerf-Seite (singleDeleteCache ohne Elternseiten) und prüft, dass WPFC
den Hook noch verarbeitet. Smoke fastest-cache-smoke.sh ersetzt den WPSC-Smoke.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/Integration/lib.sh

@@ -6,7 +6,7 @@
 # Requires jq and curl (both present in the DDEV web image).
 
 # Mutual exclusion of ALL smokes (every one sources this file inside the same web container): two at once would
-# share one site state – WP Super Cache edits wp-config.php, every smoke empties the test application passwords of the
+# share one site state – WP Fastest Cache edits wp-config.php, every smoke empties the test application passwords of the
 # admin (cleanup_app_passwords_for, harmless only because of this lock), Pods/Divi release options. The lock lives as
 # long as the script (fd 9 closes with it); a smoke that runs a second one itself must not source this file twice.
 exec 9>/tmp/lit-mcp-smoke.lock
@@ -22,7 +22,7 @@ ENDPOINT=http://localhost/wp-json/mcp/mcp-oauth-server
 HOST=$(wp option get home | sed -E 's#^[a-zA-Z]+://##')
 
 # Optional: the Host header MCP requests carry (default: curl's own, "localhost"). A cache plugin that keys its files
-# by the request's host (WP Super Cache) needs the site's real host here (super-cache-smoke.sh sets it).
+# by the request's host (WP Fastest Cache) needs the site's real host here (none of the current smokes needs it).
 MCP_HOST=${MCP_HOST:-}
 
 TOKEN=""