perf(2meet-data-optimizer): keep cached routed counts across unrelated post meta writes

- cached counts followed posts' last_changed, which WordPress moves on any
  post meta write; themes write meta on page views (on dev36 Blocksy saved a
  dynamic-CSS descriptor for each listing a crawler visited), so the cache
  was invalidated every few seconds and keyword/filter searches recounted
- counts now follow their own last_changed group (tmdo_posts), bumped on
  clean_post_cache (post saved or deleted; hooked in every mode) and on flat
  writes through the Hook Bus, plus terms' last_changed; a routed search reads
  no unmanaged meta
- Verify: PostQueryRouterFoundRowsTest (unrelated meta write keeps the count,
  save or flat write recounts), integration 588, unit 703, phpcs, stan;
  dev36 front-end
- PR: PR-117 (2.3 acceptance)

includes/class-tmdo-core.php

@@ -261,6 +261,9 @@ class TMDO_Core {
 			$post_router = new TMDO_Post_Query_Router();
 			$post_router->register_hooks();
 		}
+		if ( class_exists( 'TMDO_Post_Query_Router' ) ) {
+			add_action( 'clean_post_cache', array( 'TMDO_Post_Query_Router', 'bump_count_version' ) );
+		}
 
 		// Zone B: Warm cleanup cron handler.
 		add_action( 'wpdo_warm_cleanup', array( $this, 'cleanup_warm_zone' ) );

includes/engine/class-tmdo-hook-bus.php

@@ -912,6 +912,7 @@ final class TMDO_Hook_Bus {
 	private static function touch_posts_last_changed( string $type ): void {
 		if ( 'post' === $type ) {
 			wp_cache_set_posts_last_changed();
+			TMDO_Post_Query_Router::bump_count_version();
 		}
 	}
 

includes/query/class-tmdo-post-query-router.php

@@ -31,8 +31,11 @@
  *
  * Found rows (O-4): routed searches drop SQL_CALC_FOUND_ROWS (it counts every
  * match inside the page query); found_posts_query answers from a COUNT of the
- * same query, kept in the object cache until posts' last_changed moves (core
- * post saves, and flat writes via TMDO_Hook_Bus).
+ * same query, kept in the object cache until a post is saved or deleted, a
+ * flat write goes through TMDO_Hook_Bus (bump_count_version()) or terms'
+ * last_changed moves. Not posts' last_changed: WordPress moves it on any post
+ * meta write, which themes do on page views (Blocksy's dynamic CSS), and a
+ * routed search reads no unmanaged meta.
  *
  * 🔒 v2.9.x → v2.10.x frozen contract: never touches user entity. Routes
  * only entity_type='post'.
@@ -69,6 +72,9 @@ class TMDO_Post_Query_Router {
 	/** Object cache group for found-rows counts. */
 	private const COUNT_CACHE_GROUP = 'tmdo_found_rows';
 
+	/** The last_changed group the cached counts follow (bump_count_version()). */
+	public const COUNT_VERSION_GROUP = 'tmdo_posts';
+
 	/** Seconds a "every post of the type has a flat row" answer is reused. */
 	private const COVERAGE_TTL = 900;
 
@@ -436,7 +442,7 @@ class TMDO_Post_Query_Router {
 		// Keyword searches carry wpdb's placeholder escape for "%", which is new
 		// in every request: without it the key would never match again.
 		$stable = method_exists( $wpdb, 'remove_placeholder_escape' ) ? $wpdb->remove_placeholder_escape( $count_sql ) : $count_sql;
-		$key    = md5( $stable ) . ':' . wp_cache_get_last_changed( 'posts' );
+		$key    = md5( $stable ) . ':' . wp_cache_get_last_changed( self::COUNT_VERSION_GROUP ) . ':' . wp_cache_get_last_changed( 'terms' );
 		$total  = wp_cache_get( $key, self::COUNT_CACHE_GROUP );
 		if ( false === $total ) {
 			$total = (int) $wpdb->get_var( $count_sql );
@@ -452,6 +458,17 @@ class TMDO_Post_Query_Router {
 	// Helpers
 	// ─────────────────────────────────────────────────────────────────────────
 
+	/**
+	 * A post was saved or deleted, or a managed key written: cached routed
+	 * counts are stale. Hooked on clean_post_cache whatever the mode, so a
+	 * count cached before the router was last active is not reused.
+	 *
+	 * @return void
+	 */
+	public static function bump_count_version(): void {
+		wp_cache_set_last_changed( self::COUNT_VERSION_GROUP );
+	}
+
 	/**
 	 * Whether the router is mode-active (post mode is shadow_read or aeav_only).
 	 *