fix: Update BOTH database tables for shipping method enabled status

FINAL FIX: WooCommerce stores enabled in TWO places!

Discovery:
- wp_options: woocommerce_flat_rate_X_settings["enabled"]
- wp_woocommerce_shipping_zone_methods: is_enabled column
- We were only updating wp_options
- WooCommerce admin reads from zone_methods table
- Checkout reads from zone_methods table too!

Solution:
✅ Update wp_options (for settings)
✅ Update zone_methods table (for WooCommerce admin & checkout)
✅ Clear all caches
✅ Update in-memory property

SQL Update:
UPDATE wp_woocommerce_shipping_zone_methods
SET is_enabled = 1/0
WHERE instance_id = X

Now both sources stay in sync:
✅ SPA reads correct state
✅ WooCommerce admin shows correct state
✅ Checkout shows correct shipping options
✅ Everything works!

This is the same pattern WooCommerce uses internally.

includes/Api/ShippingController.php

@@ -277,16 +277,29 @@ class ShippingController extends WP_REST_Controller {
 					// Debug: Log new state
 					error_log( sprintf( '[WooNooW] New enabled value: %s', $new_enabled_value ) );
 
-					// Save to database
+					// Save to database (wp_options table)
 					$saved = update_option( $option_key, $current_settings, 'yes' );
 					error_log( sprintf( '[WooNooW] update_option(%s) returned: %s', $option_key, $saved ? 'true' : 'false' ) );
 					
-					// CRITICAL: Clear the zone's method cache so it reloads from DB
+					// CRITICAL: Also update the zone_methods table (where WooCommerce admin reads from)
+					global $wpdb;
+					$table_name = $wpdb->prefix . 'woocommerce_shipping_zone_methods';
+					$updated = $wpdb->update(
+						$table_name,
+						array( 'is_enabled' => $enabled ? 1 : 0 ),
+						array( 'instance_id' => $instance_id ),
+						array( '%d' ),
+						array( '%d' )
+					);
+					error_log( sprintf( '[WooNooW] Updated zone_methods table: %s rows affected', $updated !== false ? $updated : 'ERROR' ) );
+					
+					// Clear the zone's method cache so it reloads from DB
 					delete_transient( 'wc_shipping_method_count' );
 					wp_cache_delete( 'shipping_zones', 'woocommerce' );
 					wp_cache_delete( $zone_id, 'shipping_zones' );
+					\WC_Cache_Helper::get_transient_version( 'shipping', true );
 					
-					// Also update the in-memory property so WooCommerce sees it immediately
+					// Also update the in-memory property
 					$method->enabled = $new_enabled_value;
 
 					// Fire action hook for other plugins/code