cf-removal: bump 0.9.0 -> 0.10.0 + update docs

- prautoblogger.php: plugin header Version + PRAUTOBLOGGER_VERSION
- CHANGELOG.md: Removed/Changed/Note/Cost impact/Migration sections
- ARCHITECTURE.md:
  - drop 4 CF provider files from the file tree
  - drop 2 CF credential options from the wp_options table
  - drop CF Workers AI row from the External API Integrations table
  - flip Phase 3 placeholder from CF Workers AI registry to Runware
  - supersede ADR #16 with a one-line history note pointing at v0.10.0
  - update ADR #17 tail to mention the removal

readme.txt stable tag is stale (0.2.2) and clearly not maintained
inline with real releases — leaving alone in this PR; fix belongs in
a dedicated release-process cleanup.

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:           0.9.0
+ * Version:           0.10.0
  * 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', '0.9.0' );
+define( 'PRAUTOBLOGGER_VERSION', '0.10.0' );
 define( 'PRAUTOBLOGGER_DB_VERSION', '1.1.0' );
 define( 'PRAUTOBLOGGER_PLUGIN_FILE', __FILE__ );
 define( 'PRAUTOBLOGGER_PLUGIN_DIR', plugin_dir_path( __FILE__ ) );