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/UserFunc/MarketListJsonRenderer.php

@@ -18,7 +18,7 @@ use TYPO3\CMS\Frontend\ContentObject\ContentObjectRenderer;
  * UserFunc: render all VITEC markets as JSON (headless).
  *
  * Output under content.markets:
- *   { "layout": "grid|list|carousel", "markets": [ … ] }
+ *   { "layout": "grid|list|carousel|50-50", "markets": [ … ] }
  *
  * Selection semantics (FlexForm `settings.markets`):
  *   - nothing selected -> ALL visible markets, alphabetical by title
@@ -152,6 +152,7 @@ class MarketListJsonRenderer
 
             $response = [
                 'layout' => $layout,
+                'showToolbar' => (bool)($settings['showtoolbar'] ?? false),
                 'markets' => $markets,
             ];