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>

src/Integrations/FastestCache/FastestCacheIntegration.php

@@ -0,0 +1,75 @@
+<?php
+
+declare(strict_types=1);
+
+namespace LIT\MCP\Integrations\FastestCache;
+
+use LIT\MCP\Admin\CompatibilityTab;
+use LIT\MCP\ChangeLog\ChangeLog;
+use LIT\MCP\Compatibility\ProvidesCompatibility;
+use LIT\MCP\Integrations\Bootable;
+use LIT\MCP\Integrations\Integration;
+
+defined('ABSPATH') || exit;
+
+/**
+ * WP Fastest Cache: the compatibility profile (FastestCacheListener purges after writes, wired by Plugin), the
+ * cleanup of probe pages a dead check left behind and the tool lit/cache-clear – a tool group only while WP Fastest
+ * Cache is loaded.
+ */
+final class FastestCacheIntegration implements Integration, ProvidesCompatibility, Bootable
+{
+    /** @var callable(): bool */
+    private $available;
+
+    /** @param callable(): bool|null $available Whether WP Fastest Cache is loaded; null = WPFC_MAIN_PATH is defined. */
+    public function __construct(
+        ?callable $available,
+        private FastestCachePurger $purger,
+        private ChangeLog $log
+    ) {
+        $this->available = $available ?? static fn (): bool => defined('WPFC_MAIN_PATH');
+    }
+
+    public function boot(): void
+    {
+        add_action(CompatibilityTab::LOAD_ACTION, [$this, 'removeOrphans']);
+    }
+
+    /**
+     * lit_mcp_compat_profile_load('wpfc'), before any output: deletes probe pages a dead check left behind
+     * (FastestCacheProbe::removeOrphans()). A GET without nonce on purpose: only the plugin's own leftovers,
+     * idempotent.
+     */
+    public function removeOrphans(string $profileId): void
+    {
+        if ($profileId === 'wpfc' && $this->isAvailable() && current_user_can('manage_options')) {
+            FastestCacheProbe::removeOrphans();
+        }
+    }
+
+    public function id(): string
+    {
+        return 'wpfc';
+    }
+
+    public function label(): string
+    {
+        return FastestCacheCompatibility::LABEL;
+    }
+
+    public function isAvailable(): bool
+    {
+        return ($this->available)();
+    }
+
+    public function abilities(): array
+    {
+        return [new CacheClearAbility($this->purger, $this->log)];
+    }
+
+    public function compatibilities(): array
+    {
+        return [FastestCacheCompatibility::profile()];
+    }
+}