feat: live Runware model sync with 24h cache and Sync Now button (v0.15.0)

Replace hardcoded model registry with live-sync system.

New PRAutoBlogger_Runware_Model_Catalog class fetches the Runware model
catalog daily, caches in WP options (24h TTL), and falls back to the
hardcoded 15-model list if the API is unavailable. Sync Now button
in PRAdmin for on-demand refresh. Eliminates the drift that caused
silent model fallback bugs (v0.13.8, v0.14.0).

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:           0.14.0
+ * Version:           0.15.0
  * 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', '0.14.0' );
+define( 'PRAUTOBLOGGER_VERSION', '0.15.0' );
 define( 'PRAUTOBLOGGER_DB_VERSION', '1.1.0' );
 define( 'PRAUTOBLOGGER_PLUGIN_FILE', __FILE__ );
 define( 'PRAUTOBLOGGER_PLUGIN_DIR', plugin_dir_path( __FILE__ ) );