fix: resolve pre-existing PHPCS violations (Yoda conditions + short ternaries)

Fixes non-auto-fixable PHPCS errors surfaced by the estate reusable CI:
- scripts/check-constants.php: Yoda conditions at lines 140, 201
- templates/admin/ideas-browser.php: Elvis (?:) → explicit ternary (line 75)
- templates/admin/review-queue.php: Elvis (?:) → explicit ternaries (lines 144, 161-163)
- templates/admin/metabox-generation-info.php: Elvis (?:) → explicit ternaries (7 lines)
- .github/mu-plugins/prautoblogger-deploy-receiver.php: phpcs:ignore for
  ZipArchive->numFiles (native PHP property, can't be snake_cased); Elvis (?:) fix

All violations were pre-existing; none introduced by this PR.

Agent-Session: claude/adopt-ci-20260616

templates/admin/ideas-browser.php

@@ -72,7 +72,8 @@ $base_url = admin_url( 'admin.php?page=prautoblogger-ideas' );
 			<tbody>
 				<?php foreach ( $rows as $row ) : ?>
 					<?php
-					$meta       = json_decode( $row['metadata_json'] ?? '{}', true ) ?: array();
+					$decoded    = json_decode( $row['metadata_json'] ?? '{}', true );
+					$meta       = is_array( $decoded ) ? $decoded : array();
 					$suggested  = $meta['suggested_title'] ?? '';
 					$key_points = $meta['key_points'] ?? array();
 					$keywords   = $meta['target_keywords'] ?? array();