fix: final review minors m-1 to m-8

- m-1: the no-change Divi result carries preview_url/edit_url too
- m-2: overview names replace-text's per-page tree_rev
- m-3: divi-shortform documents validation_failed vs not_found for unknown IDs
- m-4: DiviWriter/DiviPageLoader final (no mocks left), neutral NewDraft
  log detail, snapshots are Etappe 4
- m-5: Tested up to 7.1, changelog completed
- m-6: content-create warns when the extras changed the stored layout
- m-7: deleting a whole section outlines nothing instead of the next one
- m-8: uninstall removes the user meta lit_mcp_log_per_page; readme lists it

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01At3V6SjwbMe6eMzVGW3Hs7

src/Integrations/WordPress/Content/ContentCreateAbility.php

@@ -34,6 +34,10 @@ defined('ABSPATH') || exit;
  */
 final class ContentCreateAbility implements Ability
 {
+    /** The extras (written after the layout) re-saved the entry and changed the stored layout (review m-6). */
+    public const LAYOUT_CHANGED = 'Der Divi-Inhalt wurde beim Speichern der Felder verändert (z. B. durch ein Plugin); '
+        . 'tree_rev beschreibt den gespeicherten Stand – vor weiteren Änderungen lit-divi-outline lesen.';
+
     public function __construct(
         private ContentSchema $schema,
         private PostWriter $writer,
@@ -161,6 +165,7 @@ final class ContentCreateAbility implements Ability
             return $draft->refuse($postId, $layout);
         }
 
+        $stored = is_array($layout) ? self::content($postId) : null;
         try {
             $this->writer->writeExtras($postId, $postType, $prepared, $input);
         } catch (Throwable $e) {
@@ -168,6 +173,9 @@ final class ContentCreateAbility implements Ability
         }
 
         $warnings = array_merge($prepared['warnings'], $layout['warnings'] ?? []);
+        if ($stored !== null && self::content($postId) !== $stored) {
+            $warnings[] = self::LAYOUT_CHANGED;
+        }
 
         return $this->result($postId, $postType, $input, $warnings, $layout);
     }
@@ -188,6 +196,13 @@ final class ContentCreateAbility implements Ability
         return $this->divi?->check($postType, self::sections($input));
     }
 
+    private static function content(int $postId): ?string
+    {
+        $post = get_post($postId);
+
+        return $post instanceof WP_Post ? (string) $post->post_content : null;
+    }
+
     /**
      * @param array<string, mixed> $input
      * @return list<mixed>

src/Integrations/WordPress/Content/NewDraft.php

@@ -106,7 +106,7 @@ final class NewDraft
             static fn () => self::deleteDraft($postId)
         );
 
-        $detail = sprintf('Extras of new post %d could not be written: %s', $postId, $cause->getMessage());
+        $detail = sprintf('Writing new post %d failed after the insert: %s', $postId, $cause->getMessage());
         if ($problems === []) {
             throw WriteFailed::rolledBack($reason, $cause, $detail);
         }