feat: deferred 1a items - menu_rev lock, lit_mcp_guides filter, warnings, schedule guard precision

Task 14 (rulings P17/P18, Q10):
- lit/menu-get returns menu_rev (Rev::ofMenu over id, parent, position,
  title, url, object, object_id); lit/menu-set-items requires it, refuses
  a stale one with rev_mismatch (hint: lit/menu-get) and returns the new
  menu_rev. Errors::revMismatch takes an optional message/hint.
- GuideRepository: filter lit_mcp_guides adds/overrides topics; invalid
  topic names and non-string content are ignored, files stay the default.
- lit/post-trash names front page, posts page and linking menus in the
  confirmation and as warnings; lit/menu-assign-location needs confirm
  to remove an assigned menu and names it; lit/post-schedule warns that
  a private entry becomes public; Divi hints no longer point to
  non-existing lit-divi-* tools.
- PostGuard::missedSchedule: 60 s publish window, zero GMT date falls
  back to get_gmt_from_date(post_date); post-schedule refuses dates
  within that window.
- write_failed after a clean rollback that keeps a revision/backup says
  "Die Aenderung wurde nicht gespeichert (... bleibt erhalten)" via the
  new state parameter (Errors::writeFailed / WriteFailed rolledBackState).
- wp-basis-smoke: menu_rev flow, unassign confirm, trash/menu and
  private-schedule warnings.

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

src/Abilities/Errors.php

@@ -56,13 +56,14 @@ final class Errors
         return self::make('not_found', $message, $hint, 404);
     }
 
-    public static function revMismatch(): WP_Error
+    /** $message/$hint replace the post-oriented defaults (e.g. for the menu lock menu_rev). */
+    public static function revMismatch(?string $message = null, ?string $hint = null): WP_Error
     {
         return self::make(
             'rev_mismatch',
-            'Der Inhalt wurde seit dem letzten Lesen geändert; nichts wurde geschrieben.',
-            'Neu lesen (z. B. lit/content-get, direkt: lit-content-get) und die Änderung auf dem aktuellen Stand '
-                . 'wiederholen.',
+            $message ?? 'Der Inhalt wurde seit dem letzten Lesen geändert; nichts wurde geschrieben.',
+            $hint ?? 'Neu lesen (z. B. lit/content-get, direkt: lit-content-get) und die Änderung auf dem aktuellen '
+                . 'Stand wiederholen.',
             409
         );
     }
@@ -105,12 +106,18 @@ final class Errors
      *
      * @param array<string, mixed> $details Extra error details (e.g. a backup that stays).
      * @param string|null          $hint    Replaces the default hint (e.g. "re-read before retrying").
+     * @param string|null          $state   Replaces "Nichts wurde gespeichert." when the rollback left
+     *                                      something behind on purpose (a backup or revision).
      */
-    public static function writeFailed(string $reason, array $details = [], ?string $hint = null): WP_Error
-    {
+    public static function writeFailed(
+        string $reason,
+        array $details = [],
+        ?string $hint = null,
+        ?string $state = null
+    ): WP_Error {
         return self::make(
             'write_failed',
-            trim('Speichern fehlgeschlagen: ' . $reason) . ' Nichts wurde gespeichert.',
+            trim('Speichern fehlgeschlagen: ' . $reason) . ' ' . ($state ?? 'Nichts wurde gespeichert.'),
             $hint ?? 'Eingaben prüfen, ggf. korrigieren und erneut versuchen; tritt der Fehler wieder auf, den '
                 . 'Administrator informieren (Details im PHP-Error-Log der Website).',
             500,
@@ -118,6 +125,16 @@ final class Errors
         );
     }
 
+    /**
+     * The $state for writeFailed() when a clean rollback deliberately keeps something, e.g.
+     * "Revision 811" or "Sicherung 88": the change itself is not saved, but "Nichts wurde
+     * gespeichert" would be untrue.
+     */
+    public static function notSavedKeeping(string $kept): string
+    {
+        return sprintf('Die Änderung wurde nicht gespeichert (%s bleibt erhalten).', $kept);
+    }
+
     /**
      * A write failed and could not be rolled back completely – something may have been saved.
      * $state and $hint replace the post-oriented defaults for writes that are not about a post

src/Abilities/Rev.php

@@ -33,6 +33,32 @@ final class Rev
         ]));
     }
 
+    /**
+     * Rev of a menu ("menu_rev", optimistic lock of lit/menu-set-items): covers, per item in
+     * menu order, exactly what lit/menu-set-items compares and writes – id, parent, position,
+     * title, url and linked object. Other item data (classes, target, …) is never rewritten
+     * by the tool and therefore not part of the lock.
+     *
+     * @param list<object> $items wp_get_nav_menu_items() result.
+     */
+    public static function ofMenu(array $items): string
+    {
+        $rows = [];
+        foreach ($items as $item) {
+            $rows[] = implode("\0", [
+                (string) (int) ($item->ID ?? 0),
+                (string) (int) ($item->menu_item_parent ?? 0),
+                (string) (int) ($item->menu_order ?? 0),
+                (string) ($item->title ?? ''),
+                (string) ($item->url ?? ''),
+                (string) ($item->object ?? ''),
+                (string) (int) ($item->object_id ?? 0),
+            ]);
+        }
+
+        return self::of('menu' . "\1" . implode("\1", $rows));
+    }
+
     /**
      * Whether $input carries the current rev of $post (optimistic lock of the post tools).
      *

src/Abilities/WriteFailed.php

@@ -15,7 +15,8 @@ use WP_Error;
  * lit_write_failed when everything was rolled back, lit_partial_write otherwise.
  * $state/$hint customise the partial-write error for writes that are not about a post (see
  * Errors::partialWrite()); $details are added to either error. $rolledBackHint replaces the
- * default hint of the write_failed error.
+ * default hint of the write_failed error, $rolledBackState its "Nichts wurde gespeichert."
+ * (for rollbacks that deliberately keep a backup or revision).
  */
 final class WriteFailed extends RuntimeException
 {
@@ -30,7 +31,8 @@ final class WriteFailed extends RuntimeException
         public readonly ?string $state = null,
         public readonly ?string $hint = null,
         public readonly array $details = [],
-        public readonly ?string $rolledBackHint = null
+        public readonly ?string $rolledBackHint = null,
+        public readonly ?string $rolledBackState = null
     ) {
         $internal = $detail !== '' ? $detail : ($previous !== null ? $previous->getMessage() : $reason);
         parent::__construct(
@@ -43,7 +45,7 @@ final class WriteFailed extends RuntimeException
     public function toError(): WP_Error
     {
         return $this->rolledBack
-            ? Errors::writeFailed($this->reason, $this->details, $this->rolledBackHint)
+            ? Errors::writeFailed($this->reason, $this->details, $this->rolledBackHint, $this->rolledBackState)
             : Errors::partialWrite(
                 $this->reason,
                 $this->postId,