feat: Wave 2 eval harness + image pipeline instrumentation (v0.13.0)

Closes #119

- Extract PRAutoBlogger_Image_Scene_Parser from image prompt builder (331→300 lines)
- Add frozen eval dataset (20 peptide topics at eval/dataset.json)
- Add LLM-as-judge scorer (gemini-flash-1.5 via OpenRouter, 3 axes)
- Add eval runner orchestrator with dry-run and Opik push support
- Add WP-CLI command: wp prautoblogger opik:eval [--limit=<n>] [--dry-run]
- Add image pipeline Opik instrumentation (image_prompt_rewrite span)
- Add content generator eval mode (suppresses publish + image gen)
- Version: v0.13.0

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:           0.12.3
+ * Version:           0.13.0
  * 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', '0.12.3' );
+define( 'PRAUTOBLOGGER_VERSION', '0.13.0' );
 define( 'PRAUTOBLOGGER_DB_VERSION', '1.1.0' );
 define( 'PRAUTOBLOGGER_PLUGIN_FILE', __FILE__ );
 define( 'PRAUTOBLOGGER_PLUGIN_DIR', plugin_dir_path( __FILE__ ) );