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/FlexForms/Usecaselist.xml

@@ -6,6 +6,57 @@
                 <sheetTitle>Usecase List</sheetTitle>
                 <type>array</type>
                 <el>
+                    <settings.layout>
+                        <label>Layout</label>
+                        <description>Display variant for the success story cards.</description>
+                        <config>
+                            <type>select</type>
+                            <renderType>selectSingle</renderType>
+                            <items>
+                                <numIndex index="0">
+                                    <label>Grid</label>
+                                    <value>grid</value>
+                                </numIndex>
+                                <numIndex index="1">
+                                    <label>List</label>
+                                    <value>list</value>
+                                </numIndex>
+                                <numIndex index="2">
+                                    <label>Carousel</label>
+                                    <value>carousel</value>
+                                </numIndex>
+                                <numIndex index="3">
+                                    <label>50 / 50</label>
+                                    <value>50-50</value>
+                                </numIndex>
+                            </items>
+                            <default>grid</default>
+                        </config>
+                    </settings.layout>
+
+                    <settings.showtoolbar>
+                        <label>Show Toolbar</label>
+                        <description>Show the toolbar above the list.</description>
+                        <config>
+                            <type>check</type>
+                            <default>0</default>
+                        </config>
+                    </settings.showtoolbar>
+
+                    <settings.usecases>
+                        <label>Success Stories</label>
+                        <description>Leave empty to show all stories (featured first, then alphabetically). If you select stories, exactly those are shown — in the order you arrange them here (use the arrows to sort).</description>
+                        <config>
+                            <type>select</type>
+                            <renderType>selectMultipleSideBySide</renderType>
+                            <foreign_table>tx_vitec_domain_model_usecase</foreign_table>
+                            <foreign_table_where>AND tx_vitec_domain_model_usecase.hidden = 0 AND tx_vitec_domain_model_usecase.deleted = 0 AND tx_vitec_domain_model_usecase.hideonwebsite = 0 ORDER BY tx_vitec_domain_model_usecase.title</foreign_table_where>
+                            <size>8</size>
+                            <minitems>0</minitems>
+                            <maxitems>999</maxitems>
+                        </config>
+                    </settings.usecases>
+
                     <settings.singlePid>
                         <label>Single PID (detail page)</label>
                         <description>Page that holds the "Show single VITEC Success Story" plugin. Used to build the detail links in the JSON output.</description>