cf-removal: patch registry, pipeline, settings, admin-page, interface

Wires out the Cloudflare Workers AI image provider across the plugin:

- class-image-pipeline.php: drop 'cloudflare' dispatch branch; Runware
  becomes the unrecognised-provider fallback
- class-image-model-registry.php: remove flux-1-schnell/cloudflare row;
  update provider-enum docblocks (runware|openrouter only)
- class-settings-fields-extended.php: remove three CF fields
  (cloudflare_ai_token, cloudflare_account_id, cf_image_via_gateway);
  drop Cloudflare mention from model-picker + NSFW retry descriptions
- class-admin-page.php: remove prautoblogger_cloudflare_ai_token from
  the encrypted-options list
- interface-image-provider.php: retarget preamble @see at Runware +
  OpenRouter; update get_provider_name() example
- class-image-nsfw-blocked.php: generalise preamble (Runware +
  OpenRouter can raise this)

Also cleans stale CF Workers AI mentions in:
class-ajax-handlers.php, interface-model-registry.php,
class-image-nsfw-retry.php, class-open-router-image-pricing.php,
prautoblogger.php.

The Cloudflare AI Gateway path (in class-open-router-config.php,
class-settings-fields.php 'prautoblogger_ai_gateway_base_url',
class-open-router-request-builder.php cache headers) is intentionally
untouched — it fronts OpenRouter and is unrelated to the CF Workers AI
image provider.

includes/services/interface-model-registry.php

@@ -5,9 +5,9 @@ declare(strict_types=1);
  * Contract for a provider-specific AI model registry.
  *
  * Phase 1 (v1): single implementation for OpenRouter (`class-open-router-model-registry.php`).
- * Phase 3: a second implementation wraps Cloudflare Workers AI model data. A
- * higher-level dispatcher iterates registered registries, calls each with the same
- * capability, and unions the results — the per-registry interface stays unchanged.
+ * Phase 3: a second implementation wraps Runware model data. A higher-level
+ * dispatcher iterates registered registries, calls each with the same capability,
+ * and unions the results — the per-registry interface stays unchanged.
  *
  * Implementations MUST:
  *   - Store the normalized registry as a WP option + transient cache layer.
@@ -86,7 +86,7 @@ interface PRAutoBlogger_Model_Registry_Interface {
 	public function get_fetched_at(): int;
 
 	/**
-	 * Machine-readable provider identifier (e.g. 'openrouter', 'cloudflare_workers_ai').
+	 * Machine-readable provider identifier (e.g. 'openrouter', 'runware').
 	 *
 	 * @return string
 	 */