fix: full-form internal links follow the {{link:}} target rules (ruling P10)

One PostIdParser for {{link:}} and select_post; post_link_url_<type> needs a
living, readable, non-attachment target of exactly that type.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

src/Integrations/Divi/Pages/DiviDynamicSourcesAbility.php

@@ -205,12 +205,12 @@ final class DiviDynamicSourcesAbility implements Ability
             return '{{post:' . $post . '}}';
         }
 
-        if (! str_starts_with($name, 'post_link_url_')) {
+        if (! str_starts_with($name, DynamicContentRules::LINK_PREFIX)) {
             return null;
         }
 
-        // Review M-9: {{link:}} refuses attachments (status inherit); internal types ("_…") are no link targets.
-        $type = substr($name, strlen('post_link_url_'));
+        // Review M-9/P10: {{link:}} and the full form refuse attachments; internal types ("_…") are no link targets.
+        $type = substr($name, strlen(DynamicContentRules::LINK_PREFIX));
 
         return $type === 'attachment' || str_starts_with($type, '_') ? null : '{{link:<ID>}}';
     }

src/Integrations/Divi/Pages/WpLinkTargets.php

@@ -10,9 +10,10 @@ use WP_Post;
 defined('ABSPATH') || exit;
 
 /**
- * {{link:<ID>}} targets from WordPress: the entry exists, lives (no trash, auto-draft or
- * revision) and the current user may read it (read_post, like select_post settings, S37).
- * Missing and unreadable entries give the same null (no existence oracle).
+ * {{link:<ID>}} and post_link_url_* targets from WordPress (ruling P10): the entry exists, lives
+ * (no trash, auto-draft or revision), is no attachment (whatever its status) and the current user
+ * may read it (read_post, like select_post settings, S37). Missing and unreadable entries give the
+ * same null (no existence oracle).
  */
 final class WpLinkTargets implements LinkTargets
 {
@@ -21,7 +22,11 @@ final class WpLinkTargets implements LinkTargets
     public function postTypeOf(int $id): ?string
     {
         $post = get_post($id);
-        if (! $post instanceof WP_Post || in_array((string) $post->post_status, self::DEAD, true)) {
+        if (
+            ! $post instanceof WP_Post
+            || in_array((string) $post->post_status, self::DEAD, true)
+            || $post->post_type === 'attachment'
+        ) {
             return null;
         }
 

src/Integrations/Divi/Pages/WpValueSanitizer.php

@@ -48,4 +48,9 @@ final class WpValueSanitizer implements ValueSanitizer
     {
         return current_user_can('read_post', $id);
     }
+
+    public function linkTargetType(int $id): ?string
+    {
+        return (new WpLinkTargets())->postTypeOf($id);
+    }
 }