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/integration/bootstrap.php

@@ -337,6 +337,9 @@ if ( ! function_exists( 'is_post_publicly_viewable' ) ) {
 		return 'publish' === ( $GLOBALS['_wp_post_status'][ (int) $post_id ] ?? 'publish' );
 	}
 }
+// 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 ] ); } }
 if ( ! function_exists( 'current_user_can' ) ) {
 	function current_user_can( string $cap, ...$args ): bool {
 		if ( ! empty( $args ) ) { $key = $cap . ':' . implode( ',', array_map( 'strval', $args ) ); if ( isset( $GLOBALS['_wp_current_user_can'][ $key ] ) ) { return (bool) $GLOBALS['_wp_current_user_can'][ $key ]; } }