fix: image style suffix empty-string bypass + image cost run_id mismatch (v0.12.2)

Bug 1: extract get_style_suffix() helper that treats '' as "use default", applied to all 3 call sites in class-image-prompt-builder.php.

Bug 2: thread $cost_tracker through ArticleWorker → Publisher → PostAssembler → ImagePipeline so image costs share the article's run_id in wp_prautoblogger_generation_log.

Version: 0.12.1 → 0.12.2
Reviewed-by: peptiderepo (CTO)
QA: qa-reviews/prautoblogger/2026-04-23-7669a9c1.md

prautoblogger.php

@@ -9,7 +9,7 @@
  * Plugin Name:       PRAutoBlogger
  * Plugin URI:        https://peptiderepo.com/prautoblogger
  * Description:       Monitors social media for trending topics, generates SEO-friendly blog posts using AI, and publishes them on a daily schedule with full cost tracking and self-improvement metrics.
- * Version:           0.12.1
+ * Version:           0.12.2
  * Requires at least: 6.0
  * Requires PHP:      7.4
  * Author:            PeptideRepo
@@ -35,7 +35,7 @@ if ( ! defined( 'ABSPATH' ) ) {
 | Defined here so every file in the plugin can reference paths, versions,
 | and limits without magic strings.
 */
-define( 'PRAUTOBLOGGER_VERSION', '0.12.1' );
+define( 'PRAUTOBLOGGER_VERSION', '0.12.2' );
 define( 'PRAUTOBLOGGER_DB_VERSION', '1.1.0' );
 define( 'PRAUTOBLOGGER_PLUGIN_FILE', __FILE__ );
 define( 'PRAUTOBLOGGER_PLUGIN_DIR', plugin_dir_path( __FILE__ ) );