feat: lit/tb-activate – the explicit switch, always a dry run first (answer F1)

- only _et_enabled; dry run in both directions lists conditions, exclusions,
  layouts, overlaps and possible overlaps (B9); confirm: true switches
- enabling needs conditions and published layouts (B10); a detached
  template needs reattach first; the default template is refused
- the off-switch reaches an attached, enabled template outside publish,
  e.g. in the trash (ruling Q16); result names the fast way back
- every switch in the change log; failed switch rolled back

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

src/Integrations/Divi/ThemeBuilder/ThemeBuilderAccess.php

@@ -157,15 +157,27 @@ class ThemeBuilderAccess
     /**
      * A template the Theme Builder tools may change (lit/tb-assign, lit/tb-activate): rights and group gate
      * (template(), a template the user may not edit reads as missing – ruling Q18), no Theme Builder draft (E7),
-     * never the default template (E8), the current template_rev.
+     * never the default template (E8), the current template_rev. $offSwitch (lit/tb-activate with enabled: false,
+     * ruling Q16): also a template visitors see although it is not published (e.g. in the trash – Divi renders
+     * every attached, enabled template, B8), so it can always be switched off; any other unpublished template
+     * still reads as missing.
      *
      * @param array<string, mixed> $input template_id, template_rev
      */
-    public function changeableTemplate(array $input): Template|WP_Error
+    public function changeableTemplate(array $input, bool $offSwitch = false): Template|WP_Error
     {
         $post = $this->template($input['template_id'] ?? null, true);
         if ($post instanceof WP_Error) {
-            return $post;
+            $id = $offSwitch && Errors::codeOf($post) === 'not_found'
+                ? $this->liveUnpublished($input['template_id'] ?? null)
+                : null;
+            if ($id === null) {
+                return $post;
+            }
+
+            $gate = $this->writableGate();
+
+            return $gate ?? $this->checkedTemplate($id, $input);
         }
 
         return $this->checkedTemplate((int) $post->ID, $input);
@@ -262,6 +274,27 @@ class ThemeBuilderAccess
         );
     }
 
+    /**
+     * ID of a template that is not published but live (listed by the live Theme Builder post and enabled) and the
+     * user may edit; null otherwise – the raw lookup of the off-switch (ruling Q16).
+     */
+    private function liveUnpublished(mixed $templateId): ?int
+    {
+        $id = PostGuard::id($templateId);
+        $post = $id === null ? null : get_post($id);
+        if (
+            ! $post instanceof WP_Post
+            || $post->post_type !== DiviThemeBuilder::TEMPLATE
+            || (string) $post->post_status === 'publish'
+            || ! $this->canEditTemplate((int) $post->ID)
+            || ! in_array((int) $post->ID, $this->store->templateIds($this->store->liveId()), true)
+        ) {
+            return null;
+        }
+
+        return $this->store->template((int) $post->ID, true)?->isLive() === true ? (int) $post->ID : null;
+    }
+
     /**
      * The draft, default and template_rev checks of changeableTemplate() for template $id (rights already checked).
      *