ver. 0.296: REST API for ordersPRO — orders management, dictionaries, API key auth

- New API layer: ApiRouter, OrdersApiController, DictionariesApiController
- Orders API: list (with filters/pagination/updated_since), details, change status, set paid/unpaid
- Dictionaries API: order statuses, transport methods, payment methods
- X-Api-Key authentication via pp_settings.api_key
- OrderRepository: listForApi(), findForApi(), touchUpdatedAt()
- updated_at column on pp_shop_orders for polling support
- api.php: skip session for API requests, route to ApiRouter
- SettingsController: api_key field in system tab
- 30 new tests (666 total, 1930 assertions)

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

updates/0.20/ver_0.296_sql.txt

@@ -0,0 +1,4 @@
+ALTER TABLE `pp_shop_orders` ADD COLUMN `updated_at` DATETIME NULL DEFAULT NULL AFTER `date_order`;
+UPDATE `pp_shop_orders` SET `updated_at` = `date_order` WHERE `updated_at` IS NULL;
+CREATE INDEX `idx_pp_shop_orders_updated_at` ON `pp_shop_orders` (`updated_at`);
+INSERT INTO `pp_settings` (`param`, `value`) VALUES ('api_key', '');