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/Guides/GuideRepositoryTest.php

@@ -4,6 +4,7 @@ declare(strict_types=1);
 
 namespace LIT\MCP\Tests\Unit\Guides;
 
+use Brain\Monkey\Filters;
 use LIT\MCP\Guides\GuideRepository;
 use LIT\MCP\Tests\Unit\TestCase;
 
@@ -48,6 +49,40 @@ final class GuideRepositoryTest extends TestCase
         ];
     }
 
+    public function testFilesAreTheDefaultWhenNoFilterIsRegistered(): void
+    {
+        Filters\expectApplied('lit_mcp_guides')->once()->with([])->andReturn([]);
+
+        self::assertSame(['divi-shortform', 'overview'], $this->guides->topics());
+        self::assertStringContainsString('Testinhalt Kurzform', (string) $this->guides->get('divi-shortform'));
+    }
+
+    public function testTheFilterAddsAndOverridesTopicsAndIgnoresInvalidNames(): void
+    {
+        Filters\expectApplied('lit_mcp_guides')->andReturn([
+            'site-rules' => "# Regeln\n<b>as-is</b>",
+            'overview' => 'Eigene Übersicht',
+            '../../wp-config' => 'nope',
+            'Upper' => 'nope',
+            'not-string' => ['nope'],
+            7 => 'nope',
+        ]);
+
+        self::assertSame(['divi-shortform', 'overview', 'site-rules'], $this->guides->topics());
+        self::assertSame("# Regeln\n<b>as-is</b>", $this->guides->get('site-rules'));
+        self::assertSame('Eigene Übersicht', $this->guides->get('overview'));
+        self::assertNull($this->guides->get('../../wp-config'));
+        self::assertNull($this->guides->get('Upper'));
+        self::assertNull($this->guides->get('not-string'));
+    }
+
+    public function testANonArrayFilterResultIsIgnored(): void
+    {
+        Filters\expectApplied('lit_mcp_guides')->andReturn('kaputt');
+
+        self::assertSame(['divi-shortform', 'overview'], $this->guides->topics());
+    }
+
     public function testMissingDirectoryYieldsNoTopics(): void
     {
         self::assertSame([], (new GuideRepository('/nonexistent/dir'))->topics());