feat(helpdesk): add Domains list page with BC OData contract type enrichment

Add a new "Domains" page to the helpdesk module that fetches domain data
from the FS_Contract_Domains OData endpoint and enriches each domain with
its contract type (PI_Header_Type) by joining with FS_Contract_Lines_Test
where Type = 'Domain'.

New files:
- domains/index().php, index(default).phtml, filter-schema.php — list page
- domains-data().php — data endpoint with PHP-side filtering/sorting
- helpdesk-domains-index.js — Grid.js via initStandardListPage()

Gateway additions:
- listDomains() — fetch all contract domains
- listDomainContractLines() — fetch domain-type contract lines for type lookup

Sidebar restructured into three collapsible groups (Lookup, Monitoring,
Administration) with per-group icons and color coding, matching the core
admin panel pattern.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

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

@@ -22,6 +22,7 @@ class BcODataGateway
     public const ENTITY_TICKET_LOG_LV = 'PBI_LV_SupportTicketLog';
     public const ENTITY_CONTRACT_LINES = 'FS_Contract_Lines_Test';
     public const ENTITY_MEETINGS = 'FS_Debitor_Meetings';
+    public const ENTITY_CONTRACT_DOMAINS = 'FS_Contract_Domains';
 
     private const CONNECT_TIMEOUT = 10;
     private const REQUEST_TIMEOUT = 30;
@@ -825,6 +826,57 @@ class BcODataGateway
         return $this->extractODataValues($response);
     }
 
+    /**
+     * Get all contract domains.
+     *
+     * Fetches all domains from the FS_Contract_Domains entity.
+     * Filtering, sorting and pagination are handled PHP-side by the caller.
+     *
+     * @return array<int, array<string, mixed>>
+     */
+    public function listDomains(): array
+    {
+        $select = 'No,Customer_No,Customer_Name,URL,State,Administration';
+        $url = $this->settingsGateway->buildEntityUrl(self::ENTITY_CONTRACT_DOMAINS)
+            . '?$top=5000'
+            . '&$select=' . rawurlencode($select)
+            . '&$orderby=' . rawurlencode('Customer_Name asc');
+
+        $response = $this->request('GET', $url);
+        if ($response === null) {
+            return [];
+        }
+
+        return $this->extractODataValues($response);
+    }
+
+    /**
+     * Get all contract lines of type "Domain".
+     *
+     * Returns contract line metadata for domain-type lines,
+     * keyed by DNS number (No field). Used to enrich the domain
+     * list with contract type information (PI_Header_Type).
+     *
+     * @return array<int, array<string, mixed>>
+     */
+    public function listDomainContractLines(): array
+    {
+        $filter = "Type eq 'Domain'";
+        $select = 'No,Header_No,PI_Header_Type,PI_Header_Description,PI_Header_State,Line_State';
+        $url = $this->settingsGateway->buildEntityUrl(self::ENTITY_CONTRACT_LINES)
+            . '?$filter=' . rawurlencode($filter)
+            . '&$top=5000'
+            . '&$select=' . rawurlencode($select)
+            . '&$orderby=' . rawurlencode('No asc');
+
+        $response = $this->request('GET', $url);
+        if ($response === null) {
+            return [];
+        }
+
+        return $this->extractODataValues($response);
+    }
+
     /**
      * Get a single ticket by ticket number.
      *