Unify list plugins, add solution list and per-story detail page

- vitec_usecaselist: layout + record selection like marketlist
- new plugin vitec_solutionlist (spec 7.13.3, key "solutions")
- tx_vitec_domain_model_usecase: detail_page -> resolved detailUrl
  (also gives story cards in vitec_modelcard a link for the first time)
- "Show Toolbar" checkbox on product/market/solution/usecase lists
- spec bumped to v1.9

BREAKING: vitec_productlist and vitec_usecaselist now emit an object
instead of a bare array. Consumers must read products.products and
usecases.usecases. Also found: productlist had a configurable layout
that was never serialised; it is emitted now, but keeps its own 0-3
vocabulary instead of grid/list/carousel.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

packages/vitec/Configuration/TCA/tx_vitec_domain_model_usecase.php

@@ -26,7 +26,7 @@ return [
         '1' => [
             'showitem' =>
                 '--div--;General,
-                    title, slug, subtitle,
+                    title, slug, detail_page, subtitle,
                 --div--;List view,
                     card_image, customer_logo, teaser,
                 --div--;Detail · Hero,
@@ -109,6 +109,17 @@ return [
                 'eval'              => 'uniqueInPid',
             ],
         ],
+        'detail_page' => [
+            'exclude'     => true,
+            'label'       => 'Detail Page',
+            'description' => 'Page that presents this story. Resolved to a URL in the JSON output; leave empty to keep using the list plugin\'s Single PID plus the slug.',
+            'config'      => [
+                'type'     => 'group',
+                'allowed'  => 'pages',
+                'size'     => 1,
+                'maxitems' => 1,
+            ],
+        ],
         'subtitle' => [
             'label'  => 'Subtitle',
             'config' => ['type' => 'input', 'size' => 40, 'eval' => 'trim', 'default' => ''],