chore(v0.8.0): version bump + CHANGELOG + ARCHITECTURE.md for image bundle

Bump plugin header and PRAUTOBLOGGER_VERSION 0.7.3 → 0.8.0. Minor bump
because Commit D removes the Image Provider dropdown from admin (a
UX-visible change), not a patch.

CHANGELOG:
- Changed: collapsed Image Provider + Model dropdowns; provider derived.
- Added: Image Prompt Instructions setting; Retry NSFW-Blocked Images
  setting.
- Fixed: silent per-image failures in the event log.

ARCHITECTURE.md:
- Stage 6b (Image Pipeline) callout now describes provider derivation
  and the NSFW-retry fallback path.
- wp_options table lists the four new/changed keys
  (`prautoblogger_image_provider` as derived, new
  `prautoblogger_image_prompt_instructions`,
  `prautoblogger_image_nsfw_retry`, and the one-shot migration flag
  `prautoblogger_migrated_image_provider_v080`).

DB schema unchanged — no PRAUTOBLOGGER_DB_VERSION bump needed.

Final commit of the v0.8.0 image bundle (thread image-mime-bug).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

prautoblogger.php

@@ -8,7 +8,7 @@ declare(strict_types=1);
  * 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:           0.7.3
+ * Version:           0.8.0
  * Requires at least: 6.0
  * Requires PHP:      7.4
  * Author:            PeptideRepo
@@ -35,7 +35,7 @@ if ( ! defined( 'ABSPATH' ) ) {
 | and limits without magic strings.
 */
 
-define( 'PRAUTOBLOGGER_VERSION', '0.7.3' );
+define( 'PRAUTOBLOGGER_VERSION', '0.8.0' );
 define( 'PRAUTOBLOGGER_DB_VERSION', '1.1.0' );
 define( 'PRAUTOBLOGGER_PLUGIN_FILE', __FILE__ );
 define( 'PRAUTOBLOGGER_PLUGIN_DIR', plugin_dir_path( __FILE__ ) );