fix: TB dry runs hide uneditable live templates, off-switch despite draft (rulings Q20, Q21)

- ThemeBuilderAccess::editableLiveTemplates() shared by tb-list and the tb-assign/tb-activate dry runs;
  uneditable live templates only as a count (hidden_overlaps, hidden_live)
- tb-activate enabled:false works while the Theme Builder has a draft, with a warning
- possible_overlaps skips identical conditions; reattach records the previous enabled state;
  exclude_from must be a list; tb-activate live from the read-back

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

src/Integrations/Divi/ThemeBuilder/Template.php

@@ -164,8 +164,11 @@ final class Template
             }
             $conditions = [];
             foreach ($other->useOn as $theirs) {
+                if (in_array($theirs, $useOn, true)) {
+                    continue; // identical: overlaps()
+                }
                 foreach ($useOn as $ours) {
-                    if ($theirs !== $ours && self::mayOverlap($theirs, $ours)) {
+                    if (self::mayOverlap($theirs, $ours)) {
                         $conditions[] = $theirs;
                         break;
                     }
@@ -179,6 +182,38 @@ final class Template
         return $overlaps;
     }
 
+    /**
+     * The overlap details of a dry run (tb-assign, tb-activate) for template $exceptId with conditions $useOn:
+     * identical and possible overlaps with the live templates the user may edit, and only the number of
+     * overlapping live templates the user may not edit (ruling Q21, Q8/B11).
+     *
+     * @param array{templates: list<Template>, hidden: list<Template>} $live ThemeBuilderAccess::editableLiveTemplates()
+     * @param list<string>                                              $useOn
+     * @return array{overlaps: list<array{id: int, title: string, conditions: list<string>}>,
+     *     possible_overlaps: list<array{id: int, title: string, conditions: list<string>}>, hidden_overlaps: int}
+     */
+    public static function overlapDetails(array $live, int $exceptId, array $useOn): array
+    {
+        $hidden = array_merge(
+            self::overlaps($live['hidden'], $exceptId, $useOn),
+            self::possibleOverlaps($live['hidden'], $exceptId, $useOn)
+        );
+
+        return [
+            'overlaps' => self::overlaps($live['templates'], $exceptId, $useOn),
+            'possible_overlaps' => self::possibleOverlaps($live['templates'], $exceptId, $useOn),
+            'hidden_overlaps' => count(array_unique(array_column($hidden, 'id'))),
+        ];
+    }
+
+    /** The sentence for hidden_overlaps > 0 (never names them). */
+    public static function hiddenOverlapsNote(int $count): string
+    {
+        return $count > 0
+            ? sprintf(' Weitere aktive Vorlagen ohne Berechtigung, die sich überschneiden können: %d.', $count)
+            : '';
+    }
+
     private static function mayOverlap(string $a, string $b): bool
     {
         foreach (self::scopesOf($a) as $x) {