fix(2meet-data-optimizer): skip cold-zone cache warming unless the cold module is active

- TMDO_Cache_Layer::prefetch() / warm_post() (and so on_save_post /
  on_loop_start) queried wp_wpdo_cold_{post_type} whenever cold fields
  were registered, even with the cold module idle and the table never
  created: every HivePress / WC save logged "table doesn't exist" errors.
  They now return unless the module is write-active and the table exists.
- CacheLayerTest activates the module in setUp; new cases assert zero cold
  queries while idle or when the table is missing.
- Verify: CacheLayerTest 12 OK; unit 671 OK, integration 480 OK,
  phpcs (phpcs.xml) 0, stan OK; dev36 live: seeding listings/products/
  vendors with cold_hp_listing idle → 0 wpdo_cold errors (was hundreds)
- PR: PR-054

includes/class-tmdo-cache-layer.php

@@ -40,7 +40,7 @@ class TMDO_Cache_Layer {
 		}
 
 		$cold_keys = TMDO_Schema_Registry::instance()->get_cold_meta_keys( $post_type );
-		if ( empty( $cold_keys ) ) {
+		if ( empty( $cold_keys ) || ! self::cold_active( $post_type ) ) {
 			return;
 		}
 
@@ -108,7 +108,7 @@ class TMDO_Cache_Layer {
 	 */
 	public static function warm_post( int $post_id, string $post_type ): void {
 		$cold_keys = TMDO_Schema_Registry::instance()->get_cold_meta_keys( $post_type );
-		if ( empty( $cold_keys ) ) {
+		if ( empty( $cold_keys ) || ! self::cold_active( $post_type ) ) {
 			return;
 		}
 
@@ -120,6 +120,19 @@ class TMDO_Cache_Layer {
 		TMDO_Zone_Cold::get_blob( $post_id, $post_type );
 	}
 
+	/**
+	 * Whether the cold zone holds data for this post type: its module writes
+	 * to the cold table and the table exists. Registered cold fields alone do
+	 * not mean either (zero side effect while the module is idle).
+	 *
+	 * @param string $post_type Post type.
+	 * @return bool
+	 */
+	private static function cold_active( string $post_type ): bool {
+		return TMDO_Feature_Flags::is_write_active( TMDO_Zone_Router::module_name( 'cold', $post_type ) )
+			&& TMDO_Schema_Manager::table_exists( TMDO_Zone_Cold::table( $post_type ) );
+	}
+
 	/**
 	 * Flush all cold cache for a post type.
 	 *