refactor: WriteFailed named constructors, Rollback runner, Errors read-back helpers (H6)

- WriteFailed::rolledBack()/partial() replace the 11-parameter constructor (now
  private); the hint/state of either error are plain $hint/$state.
- Rollback::attempt(...steps) runs every undo step and collects failure messages;
  used by ContentCreate::discard, ContentUpdate::rollBack, MediaUpdate::rollBack and
  DiviSaver::restore.
- Errors::clientMessage/codeOf/fieldsOf replace DiviReplaceTextAbility::reason,
  the JSON digging in MediaUpdateAbility::failure and ContentCreateAbility::fields.
- Errors docblock documents the exception/WP_Error split.
- ContentCreateAbility::discard takes the client reason as a parameter (both callers
  still pass REASON_EXTRAS; changing the Divi text needs a ruling).

Error payloads unchanged.

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

src/Integrations/WordPress/Status/PostCloner.php

@@ -182,13 +182,9 @@ class PostCloner
 
         if ($cloneId instanceof WP_Error || (int) $cloneId === 0) {
             $reason = $cloneId instanceof WP_Error ? $cloneId->get_error_message() : 'unknown error';
-            throw new WriteFailed(
+            throw WriteFailed::rolledBack(
                 $label . ' konnte nicht angelegt werden.',
-                true,
-                null,
-                null,
-                null,
-                sprintf('Clone (%s) of post %d could not be created: %s', $markerKey, $originalId, $reason)
+                detail: sprintf('Clone (%s) of post %d could not be created: %s', $markerKey, $originalId, $reason)
             );
         }
 
@@ -216,10 +212,10 @@ class PostCloner
         $deleted = wp_delete_post($cloneId, true);
         $detail = sprintf('Clone %d of post %d failed: %s', $cloneId, (int) $original->ID, $cause->getMessage());
         if ($deleted) {
-            throw new WriteFailed($reason, true, null, null, $cause, $detail . '; clone deleted');
+            throw WriteFailed::rolledBack($reason, $cause, $detail . '; clone deleted');
         }
 
-        throw new WriteFailed($reason, false, $cloneId, null, $cause, $detail . '; clone could not be deleted');
+        throw WriteFailed::partial($reason, $cause, $detail . '; clone could not be deleted', $cloneId);
     }
 
     /**

src/Integrations/WordPress/Status/PostReplaceWithCopyAbility.php

@@ -126,7 +126,7 @@ final class PostReplaceWithCopyAbility implements Ability
         try {
             $snapshot = $this->cloner->snapshot($original);
         } catch (Throwable $e) {
-            throw new WriteFailed(self::REASON, true, $originalId, null, $e);
+            throw WriteFailed::rolledBack(self::REASON, $e, postId: $originalId);
         }
 
         // Throws WriteFailed (backup deleted again) before anything touches the original.
@@ -275,13 +275,12 @@ final class PostReplaceWithCopyAbility implements Ability
                 sprintf('"%s": Austausch nur teilweise zurückgenommen', $original->post_title),
                 $revisionId
             );
-            throw new WriteFailed(
+            throw WriteFailed::partial(
                 self::REASON,
-                false,
-                $originalId,
-                $revisionId,
                 $cause,
                 $detail . '; rollback incomplete: ' . $e->getMessage(),
+                $originalId,
+                $revisionId,
                 sprintf(
                     'Eintrag %d ist möglicherweise teilweise geändert worden (Stand vorher: Revision %s); die '
                         . 'vollständige Sicherung des vorherigen Stands liegt als Eintrag %d im Papierkorb.',
@@ -297,17 +296,14 @@ final class PostReplaceWithCopyAbility implements Ability
             );
         }
 
-        throw new WriteFailed(
+        throw WriteFailed::rolledBack(
             self::REASON,
-            true,
-            $originalId,
-            $revisionId,
             $cause,
             $detail,
-            null,
-            null,
-            $details,
-            rolledBackState: Errors::notSavedKeeping(sprintf('Sicherung %d im Papierkorb', $backupId))
+            state: Errors::notSavedKeeping(sprintf('Sicherung %d im Papierkorb', $backupId)),
+            details: $details,
+            postId: $originalId,
+            revisionId: $revisionId
         );
     }
 

src/Integrations/WordPress/Status/StatusWrite.php

@@ -33,16 +33,13 @@ final class StatusWrite
                 sprintf('"%s": Statusänderung abgebrochen, Stand unklar', $post->post_title)
             );
 
-            throw new WriteFailed(
+            throw WriteFailed::partial(
                 $reason,
-                false,
-                $postId,
-                null,
                 $e,
-                '',
-                sprintf('Status von Eintrag %d ist möglicherweise schon geändert worden.', $postId),
-                'Den Aufruf nicht einfach wiederholen. Zuerst mit lit/content-get (direkt: lit-content-get) Status '
-                    . 'und Inhalt prüfen und dem Nutzer Bescheid geben.'
+                postId: $postId,
+                state: sprintf('Status von Eintrag %d ist möglicherweise schon geändert worden.', $postId),
+                hint: 'Den Aufruf nicht einfach wiederholen. Zuerst mit lit/content-get (direkt: lit-content-get) '
+                    . 'Status und Inhalt prüfen und dem Nutzer Bescheid geben.'
             );
         }
     }