refactor: rename src/ to source/ and update all CI references

- Rename project source directory from src/ to source/
- Update CI workflows (ci-joomla, pr-check, repo-health) to check
  source/ first, falling back to src/ and htdocs/ for compat
- Update .gitignore vendor exception path
- manifest.xml entry-point already updated

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

source/packages/com_mokoog/src/Controller/DisplayController.php

@@ -0,0 +1,25 @@
+<?php
+
+/**
+ * @package     MokoJoomOpenGraph
+ * @subpackage  com_mokoog
+ * @author      Moko Consulting <hello@mokoconsulting.tech>
+ * @copyright   Copyright (C) 2026 Moko Consulting. All rights reserved.
+ * @license     GNU General Public License version 3 or later; see LICENSE
+ */
+
+namespace Joomla\Component\MokoOG\Administrator\Controller;
+
+defined('_JEXEC') or die;
+
+use Joomla\CMS\MVC\Controller\BaseController;
+
+class DisplayController extends BaseController
+{
+    /**
+     * The default view.
+     *
+     * @var string
+     */
+    protected $default_view = 'tags';
+}