add composer-unused, comprehensive docs, and project restructure

- Add icanhazstring/composer-unused as dev dependency for dependency hygiene checks
- Add German documentation (docs/) covering architecture, conventions, workflows, and developer checklists
- Add API layer (ApiAuth, ApiBootstrap, ApiResponse), audit, scheduler, custom fields, and SSO services
- Add Microsoft OIDC SSO, API token management, and user lifecycle features
- Add swagger-ui vendor integration and OpenAPI spec
- Add production Docker setup and bin/ scripts
- Update composer dependencies, config, templates, and frontend assets throughout

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

lib/Repository/Org/UserDepartmentRepository.php

@@ -45,10 +45,69 @@ class UserDepartmentRepository
         $query = 'delete ud from user_departments ud ' .
             'where ud.department_id = ? and not exists (' .
             'select 1 from user_tenants ut ' .
-            'join tenant_departments td on td.tenant_id = ut.tenant_id ' .
-            'where ut.user_id = ud.user_id and td.department_id = ud.department_id' .
+            'join departments d on d.id = ud.department_id ' .
+            'where ut.user_id = ud.user_id and ut.tenant_id = d.tenant_id' .
             ')';
         $result = DB::delete($query, (string) $departmentId);
         return $result !== false ? (int) $result : 0;
     }
+
+    public static function countUsersByDepartmentIds(array $departmentIds): array
+    {
+        return self::countByDepartmentIds($departmentIds, false);
+    }
+
+    public static function countActiveUsersByDepartmentIds(array $departmentIds): array
+    {
+        return self::countByDepartmentIds($departmentIds, true);
+    }
+
+    private static function countByDepartmentIds(array $departmentIds, bool $activeOnly): array
+    {
+        $departmentIds = array_values(array_unique(array_map('intval', $departmentIds)));
+        $departmentIds = array_values(array_filter($departmentIds, static fn ($id) => $id > 0));
+        if (!$departmentIds) {
+            return [];
+        }
+
+        $placeholders = implode(',', array_fill(0, count($departmentIds), '?'));
+        $joinUsersSql = $activeOnly ? ' join users u on u.id = ud.user_id and u.active = 1' : '';
+        $rows = DB::select(
+            'select ud.department_id, count(distinct ud.user_id) as user_count from user_departments ud' .
+            $joinUsersSql .
+            ' where ud.department_id in (' . $placeholders . ') group by ud.department_id',
+            ...array_map('strval', $departmentIds)
+        );
+
+        if (!is_array($rows)) {
+            return [];
+        }
+
+        $result = [];
+        foreach ($rows as $row) {
+            $departmentId = self::extractIntField($row, 'department_id');
+            if ($departmentId <= 0) {
+                continue;
+            }
+            $result[$departmentId] = self::extractIntField($row, 'user_count');
+        }
+
+        return $result;
+    }
+
+    private static function extractIntField(array $row, string $field): int
+    {
+        foreach ($row as $value) {
+            if (!is_array($value)) {
+                continue;
+            }
+            if (array_key_exists($field, $value)) {
+                return (int) $value[$field];
+            }
+        }
+        if (array_key_exists($field, $row)) {
+            return (int) $row[$field];
+        }
+        return 0;
+    }
 }