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/Classes/Controller/SolutionController.php

@@ -45,6 +45,19 @@ class SolutionController extends ActionController
      *
      * @return ResponseInterface
      */
+    /**
+     * action list
+     *
+     * Intentionally empty: in headless mode the JSON is produced by
+     * SolutionListJsonRenderer through TypoScript, so this action never runs.
+     * It exists because configurePlugin() needs a target - same as
+     * MarketController::listAction().
+     */
+    public function listAction(): ResponseInterface
+    {
+        return $this->htmlResponse();
+    }
+
     public function showAction(): ResponseInterface
     {
         $selectedSolutionId = (int)$this->settings['solution'];