fix: attach images immediately + upgrade image prompts to v2

Two fixes:

1. Image attachment: moved set_post_thumbnail() and Image B post meta
   into generate_and_attach_images() so they persist immediately after
   each image generates. Previously the caller set them after both images
   completed — if the process timed out (common with GPT-5 Image at
   ~30s/image), the featured image was never attached and Image B was
   never attempted.

2. Image prompts: replaced FLUX.1-optimized rewriter system prompt and
   90s infomercial style suffix with prompts optimized for Gemini Flash
   Image and GPT-5 Image. New style: premium scientific lifestyle
   photography with golds/teals color grading. Includes one-time migration
   to update stored style suffix.

Also logs when Image B is skipped due to missing source data (previously
silent), helping diagnose why some posts only get one image.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

includes/core/class-image-pipeline.php

@@ -138,6 +138,15 @@ class PRAutoBlogger_Image_Pipeline {
 		$image_a_result = $this->generate_image_a( $post_id, $article_data );
 		if ( ! is_wp_error( $image_a_result ) && isset( $image_a_result['attachment_id'] ) ) {
 			$result['image_a_id'] = $image_a_result['attachment_id'];
+
+			// Set featured image immediately so it persists even if the
+			// process times out before Image B finishes or before the
+			// caller gets to handle the return value.
+			set_post_thumbnail( $post_id, $image_a_result['attachment_id'] );
+			PRAutoBlogger_Logger::instance()->info(
+				sprintf( 'Set featured image (attachment %d) for post %d', $image_a_result['attachment_id'], $post_id ),
+				'image_pipeline'
+			);
 		} else {
 			$result['errors'][] = is_wp_error( $image_a_result )
 				? $image_a_result->get_error_message()
@@ -152,6 +161,14 @@ class PRAutoBlogger_Image_Pipeline {
 			$image_b_result = $this->generate_image_b( $post_id, $source_data );
 			if ( ! is_wp_error( $image_b_result ) && isset( $image_b_result['attachment_id'] ) ) {
 				$result['image_b_id'] = $image_b_result['attachment_id'];
+
+				// Store Image B reference immediately for the same
+				// timeout-resilience reason as Image A above.
+				update_post_meta( $post_id, '_prautoblogger_image_b_id', $image_b_result['attachment_id'] );
+				PRAutoBlogger_Logger::instance()->info(
+					sprintf( 'Stored Image B (attachment %d) for post %d', $image_b_result['attachment_id'], $post_id ),
+					'image_pipeline'
+				);
 			} else {
 				$result['errors'][] = is_wp_error( $image_b_result )
 					? $image_b_result->get_error_message()
@@ -160,6 +177,11 @@ class PRAutoBlogger_Image_Pipeline {
 			if ( ! is_wp_error( $image_b_result ) ) {
 				$result['cost_usd'] += $image_b_result['cost_usd'] ?? 0.0;
 			}
+		} else {
+			PRAutoBlogger_Logger::instance()->info(
+				sprintf( 'Image B skipped for post %d: no source data available.', $post_id ),
+				'image_pipeline'
+			);
 		}
 
 		return $result;

includes/core/class-image-prompt-builder.php

@@ -28,17 +28,22 @@ class PRAutoBlogger_Image_Prompt_Builder {
 	 * code review, not an admin-panel click.
 	 */
 	private const REWRITER_SYSTEM_PROMPT = <<<'PROMPT'
-You are an image-prompt specialist for FLUX.1, a text-to-image model.
+You are an image-prompt specialist for premium AI image models (Gemini Flash Image, GPT-5 Image).
 
-Given an article title and summary, output ONE short paragraph (2-4 sentences, under 60 words) describing a concrete visual scene that would make a compelling featured image for the article.
+Given an article title and summary about peptides, supplements, or biohacking, write ONE vivid scene description (2-3 sentences, under 80 words) for a compelling featured image. Emphasize:
+- OBJECTS and MATERIALS: lab glassware, peptide vials, molecular structures, syringes, supplement bottles, biometric devices, microscopes, fitness equipment, test tubes
+- LIGHTING and DEPTH: bright directional studio lighting, selective focus, rich warm/cool color contrasts
+- COMPOSITION: dynamic framing with clear focal point, professional product photography perspective, sense of scale and precision
+- MOOD: scientific credibility paired with aspirational wellness — premium feel, approachable, engaging
 
-Rules:
-- Describe OBJECTS, SETTING, LIGHTING, COMPOSITION, and MOOD — not abstract concepts.
-- Never include text, words, labels, logos, or watermarks in the scene.
-- Never describe people's faces in detail (FLUX.1 struggles with faces). Use silhouettes, hands, or over-the-shoulder framings instead.
-- Focus on the article's core SUBJECT as a physical thing: lab equipment, supplements, syringes, molecules, gym settings, packaging, etc.
-- Do NOT include any style direction — that is appended separately.
-- Output ONLY the scene description. No preamble, no explanation, no quotes.
+Avoid:
+- Abstract concepts; show concrete objects only
+- Text, logos, watermarks, or readable labels
+- Detailed human faces (use hands, torso, silhouettes, or exclude people)
+- Multiple competing visual elements; keep the subject dominant
+- Generic stock-photo composition
+
+Output ONLY the scene description — no preamble, explanation, or quotes. Do NOT include any style direction; that is appended separately.
 PROMPT;
 
 	/**

includes/core/class-post-assembler.php

@@ -138,24 +138,12 @@ class PRAutoBlogger_Post_Assembler {
 		$source_data = ( new PRAutoBlogger_Source_Collector() )->get_source_data_for_image( $idea->get_source_ids() );
 
 		try {
+			// The pipeline now sets featured image and Image B meta
+			// internally, immediately after each image generates. This
+			// ensures attachment persists even if the process times out
+			// before this method returns.
 			$result = ( new PRAutoBlogger_Image_Pipeline() )->generate_and_attach_images( $post_id, $post_data, $source_data );
 
-			if ( isset( $result['image_a_id'] ) ) {
-				set_post_thumbnail( $post_id, $result['image_a_id'] );
-				PRAutoBlogger_Logger::instance()->info(
-					sprintf( 'Set featured image (attachment %d) for post %d', $result['image_a_id'], $post_id ),
-					'publisher'
-				);
-			}
-
-			if ( isset( $result['image_b_id'] ) ) {
-				update_post_meta( $post_id, '_prautoblogger_image_b_id', $result['image_b_id'] );
-				PRAutoBlogger_Logger::instance()->info(
-					sprintf( 'Stored Image B (attachment %d) for post %d', $result['image_b_id'], $post_id ),
-					'publisher'
-				);
-			}
-
 			if ( ! empty( $result['errors'] ) ) {
 				foreach ( $result['errors'] as $error ) {
 					PRAutoBlogger_Logger::instance()->warning( 'Image warning for post ' . $post_id . ': ' . $error, 'publisher' );