feat: lit/tb-assign – conditions with dry run on live templates, reattach

- ThemeBuilderAccess::changeableTemplate(): rights (Q18 not_found), group gate,
  no TB draft, never the default template, current template_rev
- omitted exclude_from stays, [] clears (Q3); live dry run shows use_on and
  exclude_from before/after, overlaps and possible overlaps (B9)
- reattach only with published layouts (B10) and a live TB post; always
  disabled, unmarks template and layouts; failure restores everything

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

tests/Unit/Integrations/Divi/ThemeBuilder/TemplateTest.php

@@ -92,4 +92,41 @@ final class TemplateTest extends TestCase
         );
         self::assertSame([], Template::overlaps([$other], 1070, ['homepage']));
     }
+
+    /** Ruling Q8/B9: conditions of the same family may overlap (Divi then picks one template). */
+    public function testPossibleOverlapsNameOtherLiveTemplatesOfTheSameFamily(): void
+    {
+        $pages = ThemeBuilderFixtures::template(1070, [
+            'enabled' => true,
+            'title' => 'Seiten',
+            'use_on' => ['singular:post_type:page:all', 'search'],
+        ]);
+        $archives = ThemeBuilderFixtures::template(1071, ['enabled' => true, 'title' => 'Archive', 'use_on' => ['archive:all']]);
+        $inTerm = ThemeBuilderFixtures::template(1072, [
+            'enabled' => true,
+            'title' => 'Beiträge einer Kategorie',
+            'use_on' => ['singular:taxonomy:category:term:id:5'],
+        ]);
+        $disabled = ThemeBuilderFixtures::template(1073, ['use_on' => ['singular:post_type:page:all']]);
+        $live = [$pages, $archives, $inTerm, $disabled];
+
+        self::assertSame(
+            [
+                ['id' => 1070, 'title' => 'Seiten', 'conditions' => ['singular:post_type:page:all']],
+                ['id' => 1072, 'title' => 'Beiträge einer Kategorie', 'conditions' => ['singular:taxonomy:category:term:id:5']],
+            ],
+            Template::possibleOverlaps($live, 1066, ['singular:post_type:page:id:1053'])
+        );
+        self::assertSame(
+            [['id' => 1071, 'title' => 'Archive', 'conditions' => ['archive:all']]],
+            Template::possibleOverlaps($live, 1066, ['archive:taxonomy:category:term:id:5'])
+        );
+        self::assertSame([], Template::possibleOverlaps($live, 1066, ['search']), 'identical ones are overlaps()');
+        self::assertSame([], Template::possibleOverlaps($live, 1066, ['404']));
+        self::assertSame(
+            ['id' => 1070, 'title' => 'Seiten', 'conditions' => ['singular:post_type:page:all']],
+            Template::possibleOverlaps($live, 1066, ['homepage'])[0],
+            'a static front page is a page'
+        );
+    }
 }