fix(2meet-data-optimizer): filter REST listings collection by post_status and post_type

- GET /wpdo/v1/listings rejects unregistered or non-viewable post types (400) and joins posts so Zone A only lists published posts of that type
- WP_Query fallback now returns only show_in_rest hot columns, matching the Zone A path
- Verify: core unit 605 / integration 432 OK (new RestApi tests); 1M bench: page 7ms, total COUNT 0.12s → 1.7s (tracked in PR-030)
- PR: PR-015

tests/bootstrap.php

@@ -426,6 +426,18 @@ if ( ! function_exists( 'wp_cache_delete' ) ) {
 	function wp_cache_delete( $key, $group = '' ): bool { unset( $GLOBALS['_wp_cache'][ $group ][ $key ] ); return true; }
 }
 
+// Registered post types: name => publicly viewable (bool).
+if ( ! function_exists( 'post_type_exists' ) ) {
+	function post_type_exists( string $post_type ): bool {
+		return isset( $GLOBALS['_wp_registered_post_types'][ $post_type ] );
+	}
+}
+if ( ! function_exists( 'is_post_type_viewable' ) ) {
+	function is_post_type_viewable( $post_type ): bool {
+		return ! empty( $GLOBALS['_wp_registered_post_types'][ (string) $post_type ] );
+	}
+}
+
 // ── Stub classes ───────────────────────────────────────────────────────────
 
 if ( ! class_exists( 'WP_Query' ) ) {
@@ -434,7 +446,7 @@ if ( ! class_exists( 'WP_Query' ) ) {
 		public int   $found_posts = 0;
 		public int   $max_num_pages = 0;
 		private array $args       = [];
-		public function __construct( array $args = [] ) { $this->args = $args; }
+		public function __construct( array $args = [] ) { $this->args = $args; $this->posts = $GLOBALS['_wp_query_posts'] ?? []; }
 		public function get( string $key, $default = '' ) { return $this->args[ $key ] ?? $default; }
 		public function set( string $key, $value ): void { $this->args[ $key ] = $value; }
 	}