feat(helpdesk): refactor multi-tenant BC settings and risk radar improvements

Restructure helpdesk tenant settings into per-connection config with
improved token handling. Update risk radar data endpoint and UI.
Clean up ImageUploadTrait and update architecture contract tests.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

modules/helpdesk/lib/Module/Helpdesk/Service/RiskRadarService.php

@@ -337,24 +337,6 @@ final class RiskRadarService
         return ($days * 86400) + ($hours * 3600) + ($minutes * 60) + $seconds;
     }
 
-    /**
-     * @param array<int, int> $values
-     */
-    private static function median(array $values): ?float
-    {
-        if ($values === []) {
-            return null;
-        }
-
-        sort($values);
-        $count = count($values);
-        $mid = intdiv($count, 2);
-
-        return $count % 2 === 0
-            ? round(($values[$mid - 1] + $values[$mid]) / 2, 1)
-            : (float) $values[$mid];
-    }
-
     private static function parseTimestamp(string $value): ?int
     {
         $value = trim($value);