feat: WooCommerce Business Central integration plugin

Native PHP plugin (no Composer) that syncs:
- Product stock and pricing from BC to WooCommerce (scheduled cron)
- Orders from WooCommerce to BC (on payment received)
- Auto-creates customers in BC from WooCommerce billing data

Product matching: WooCommerce SKU → BC Item Number, fallback to GTIN (EAN).
OAuth2 client credentials auth with encrypted secret storage.
Admin settings page with connection test, manual sync, and log viewer.

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

woo-business-central/uninstall.php

@@ -0,0 +1,75 @@
+<?php
+/**
+ * Uninstall WooCommerce Business Central Integration
+ *
+ * @package WooBusinessCentral
+ */
+
+// Exit if uninstall not called from WordPress
+if ( ! defined( 'WP_UNINSTALL_PLUGIN' ) ) {
+    exit;
+}
+
+// Check if user wants to delete data (optional, could be a setting)
+$delete_data = get_option( 'wbc_delete_data_on_uninstall', 'no' );
+
+// Always delete these options
+$options_to_delete = array(
+    'wbc_tenant_id',
+    'wbc_client_id',
+    'wbc_client_secret',
+    'wbc_environment',
+    'wbc_company_id',
+    'wbc_sync_frequency',
+    'wbc_enable_stock_sync',
+    'wbc_enable_price_sync',
+    'wbc_enable_order_sync',
+    'wbc_default_payment_terms_id',
+    'wbc_default_shipment_method_id',
+    'wbc_shipping_item_number',
+    'wbc_last_sync_time',
+    'wbc_encryption_key',
+    'wbc_delete_data_on_uninstall',
+);
+
+foreach ( $options_to_delete as $option ) {
+    delete_option( $option );
+}
+
+// Delete transients
+delete_transient( 'wbc_access_token' );
+
+// Clear scheduled events
+$sync_timestamp = wp_next_scheduled( 'wbc_product_sync_event' );
+if ( $sync_timestamp ) {
+    wp_unschedule_event( $sync_timestamp, 'wbc_product_sync_event' );
+}
+
+$cleanup_timestamp = wp_next_scheduled( 'wbc_log_cleanup_event' );
+if ( $cleanup_timestamp ) {
+    wp_unschedule_event( $cleanup_timestamp, 'wbc_log_cleanup_event' );
+}
+
+// Drop logs table
+global $wpdb;
+$table_name = $wpdb->prefix . 'wbc_logs';
+$wpdb->query( "DROP TABLE IF EXISTS $table_name" );
+
+// Delete user meta (BC customer IDs)
+$wpdb->query( "DELETE FROM {$wpdb->usermeta} WHERE meta_key IN ('_wbc_bc_customer_id', '_wbc_bc_customer_number')" );
+
+// Delete post meta (BC item info, order sync info)
+$wpdb->query( "DELETE FROM {$wpdb->postmeta} WHERE meta_key LIKE '_wbc_%'" );
+
+// Delete order meta for HPOS (if using custom order tables)
+if ( class_exists( 'Automattic\WooCommerce\Utilities\OrderUtil' ) ) {
+    if ( Automattic\WooCommerce\Utilities\OrderUtil::custom_orders_table_usage_is_enabled() ) {
+        $orders_table = $wpdb->prefix . 'wc_orders_meta';
+        if ( $wpdb->get_var( "SHOW TABLES LIKE '$orders_table'" ) === $orders_table ) {
+            $wpdb->query( "DELETE FROM $orders_table WHERE meta_key LIKE '_wbc_%'" );
+        }
+    }
+}
+
+// Clear any cached data
+wp_cache_flush();