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

tests/Unit/Integrations/WordPress/Menus/MenuReadAbilitiesTest.php

@@ -5,6 +5,7 @@ declare(strict_types=1);
 namespace LIT\MCP\Tests\Unit\Integrations\WordPress\Menus;
 
 use Brain\Monkey\Functions;
+use LIT\MCP\Abilities\Rev;
 use LIT\MCP\Integrations\WordPress\Menus\MenuGetAbility;
 use LIT\MCP\Integrations\WordPress\Menus\MenuListAbility;
 use LIT\MCP\Tests\Unit\TestCase;
@@ -48,6 +49,8 @@ final class MenuReadAbilitiesTest extends TestCase
 
         self::assertSame('Hauptmenü', $result['name']);
         self::assertSame('Start', $result['items'][0]['title']);
+        self::assertSame(Rev::ofMenu([self::item(10, 0, 'Start')]), $result['menu_rev']);
+        self::assertContains('menu_rev', $ability->outputSchema()['required']);
         self::assertSame('lit_not_found', $ability->execute(['menu_id' => 9])->get_error_code());
     }