test: 建立 phpunit 測試基建並移植 25 個 HivePress 測試

AddOn 先前 tests=0。新增：
- composer.json（dev 依賴 + phpunit/phpcs script）
- phpunit.xml（failOnWarning=true）
- tests/bootstrap.php：直接 require 核心 plugin 的 unit bootstrap，避免複製
  ~700 行 WP stub，再載入本 AddOn 的類別；補 trait wrapper 與自動 WPDO_ alias
  （includes/back-compat-aliases.php 掛在 plugins_loaded:7，PHPUnit 下不會跑）
- tests/unit/ 25 個測試 + WpdbMockTrait（自 A 移植）

生產碼一併修對外契約：interface-tmdo-hp-adapter.php 改為先宣告空的
WPDO_HivePress_Adapter、再讓 TMDO_HivePress_Adapter extends 它（PHP 無法
class_alias 介面，只有繼承能讓 instanceof WPDO_HivePress_Adapter 對
implements TMDO_ 名稱的 adapter 成立）。與核心 interface-entity-adapter.php
同一模式。這也讓第三方自訂 adapter 用舊介面名仍可通過核心檢查。

145 tests / 357 assertions GREEN

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TbG1keQQ7XBa7qMQY16KCY

includes/hivepress/interface-tmdo-hp-adapter.php

@@ -38,7 +38,15 @@ if ( ! interface_exists( 'TMDO_HivePress_Adapter' ) ) {
 	 * everything except `plugin_slug()` / `detection_class()` / `detection_const()`,
 	 * so concrete adapters typically override 3–6 methods.
 	 */
-	interface TMDO_HivePress_Adapter {
+	// Back-compat: declare the WPDO_ marker first so TMDO_ can extend it.
+	// PHP class_alias() does not work on interfaces; inheritance is the only way
+	// to make `instanceof WPDO_HivePress_Adapter` true for adapters implementing
+	// the TMDO_ name. Mirrors the core's interface-entity-adapter.php.
+	if ( ! interface_exists( 'WPDO_HivePress_Adapter', false ) ) {
+		interface WPDO_HivePress_Adapter {}
+	}
+
+	interface TMDO_HivePress_Adapter extends WPDO_HivePress_Adapter {
 
 		/**
 		 * Stable slug used as Schema_Registry / Custom_Table_Registry provider key.