Solution detail page and a single LinkResolver

Closes two annex items that turned out to be the same defect seen from two
sides: markets could link to a detail page, solutions could not, and the code
that turns a page uid into a URL existed four times over.

detail_page for Solution (B-11)
- ext_tables.sql, TCA (group on pages, maxitems 1, in showitem behind slug)
  and Domain\Model\Solution mirror the Market field exactly
- SolutionShowJsonRenderer emits detailUrl
- ModelcardJsonRenderer serialized no detailUrl at all: its shared
  market|solution branch never carried the field. Market modelcards therefore
  gain a link here too, not just solutions.

Service\LinkResolver (B-12)
- one implementation replaces four private copies (Market list/show, Usecase
  list/show). The copies had drifted: Market returned null on failure, Usecase
  an empty string. The contract is now explicit -- null means "no link".
- Usecase keeps a thin resolvePageUrl() wrapper appending ?? '', because it
  concatenates paths and a null would tear the strings apart.
- LocationsJsonRenderer and NewsJsonRenderer stay out on purpose: they resolve
  a full parameter construct resp. slug paths plus canonical, which is not
  page-uid-to-URL and does not fit the same contract.

Requires on the server, the column exists in code only:
    vendor/bin/typo3 database:updateschema "*.add,*.change"
    vendor/bin/typo3 cache:flush

packages/vitec/Classes/UserFunc/MarketListJsonRenderer.php

@@ -5,13 +5,13 @@ declare(strict_types=1);
 namespace Evomedien\Vitec\UserFunc;
 
 use Doctrine\DBAL\ParameterType;
+use Evomedien\Vitec\Service\LinkResolver;
 use Evomedien\Vitec\Service\RteResolver;
 use Evomedien\Vitec\Service\UsecaseSerializer;
 use TYPO3\CMS\Core\Attribute\AsAllowedCallable;
 use TYPO3\CMS\Core\Database\ConnectionPool;
 use TYPO3\CMS\Core\Service\FlexFormService;
 use TYPO3\CMS\Core\Utility\GeneralUtility;
-use TYPO3\CMS\Frontend\ContentObject\ContentObjectRenderer;
 
 /**
  * UserFunc: render all VITEC markets as JSON (headless).
@@ -168,29 +168,8 @@ class MarketListJsonRenderer
             'subtitle' => (string)($r['subtitle'] ?? ''),
             'teaser' => (string)($r['teaser'] ?? ''),
             'description' => RteResolver::html($r['description'] ?? ''),
-            'detailUrl' => $this->detailUrl((int)($r['detail_page'] ?? 0)),
+            'detailUrl' => LinkResolver::pageUrl((int)($r['detail_page'] ?? 0)),
             'image' => $serializer->image($uid, 'image', self::TABLE, true),
         ];
     }
-
-    /**
-     * Resolve the `detail_page` uid to a URL. The frontend cannot do anything
-     * with a raw page uid, so the link is built server side — same convention
-     * as `headerLink` and LocationsJsonRenderer.
-     *
-     * Returns null when no page is set or the link cannot be resolved.
-     */
-    private function detailUrl(int $pageUid): ?string
-    {
-        if ($pageUid <= 0) {
-            return null;
-        }
-        try {
-            $cObj = GeneralUtility::makeInstance(ContentObjectRenderer::class);
-            $url = $cObj->typoLink_URL(['parameter' => (string)$pageUid]);
-            return $url !== '' ? $url : null;
-        } catch (\Throwable $e) {
-            return null;
-        }
-    }
 }