Add Oribi Sync plugin for syncing WordPress pages and theme files from a Git repository

- Implement encryption helpers for storing and retrieving the Personal Access Token (PAT).
- Create REST API endpoints for triggering sync, checking sync status, and handling webhooks.
- Develop the sync engine to fetch pages from the Git repository, create/update WordPress pages, and trash removed pages.
- Add functionality for previewing and applying theme files from the repository.
- Set up plugin activation and deactivation hooks to manage default options and scheduled tasks.
- Implement uninstall routine to clean up plugin options and metadata from posts.

uninstall.php

@@ -0,0 +1,36 @@
+<?php
+/**
+ * Oribi Sync — Uninstall routine.
+ *
+ * Called by WordPress when the plugin is deleted via the admin UI.
+ * Removes all plugin options from the database.
+ */
+
+if ( ! defined( 'WP_UNINSTALL_PLUGIN' ) ) exit;
+
+delete_option( 'oribi_sync_repo' );
+delete_option( 'oribi_sync_branch' );
+delete_option( 'oribi_sync_provider' );
+delete_option( 'oribi_sync_pat' );
+delete_option( 'oribi_sync_last_run' );
+delete_option( 'oribi_sync_log' );
+delete_option( 'oribi_sync_webhook_secret' );
+delete_option( 'oribi_sync_theme_applied' );
+
+// Remove sync metadata from posts
+$posts = get_posts( [
+    'post_type'      => 'page',
+    'post_status'    => 'any',
+    'posts_per_page' => -1,
+    'meta_key'       => '_oribi_sync_checksum',
+    'fields'         => 'ids',
+] );
+
+foreach ( $posts as $post_id ) {
+    delete_post_meta( $post_id, '_oribi_sync_checksum' );
+    delete_post_meta( $post_id, '_oribi_sync_source' );
+    delete_post_meta( $post_id, '_oribi_sync_last_run' );
+}
+
+// Clear any scheduled cron
+wp_clear_scheduled_hook( 'oribi_sync_cron_run' );