build: 移植 PHPCS + PHPStan L6 品質 gate（PR-I 前半）

- phpcs.xml（自 A 移植）：ruleset 改名、*/tools/* 例外換成 */back-compat/*、
  中文註解全域排除 Squiz.Commenting.InlineComment.InvalidEndChar、
  interface 別名檔排除 OneObjectStructurePerFile
- 檔頭正規化：16 個檔案的 declare(strict_types=1) 與前導 // 註解移到
  file docblock 之後，並移除 <?php 後多餘空行（phpcbf 另自動修 190 處）
- phpstan.neon + .phpstan/stubs.php（TMDO_ 與 WPDO_ 兩套常數）+
  重新產生的 phpstan-baseline.neon（710 errors，A 的 3877 行 baseline
  因前綴與路徑不同無法沿用）

現況：PHPCS 0 errors / 0 warnings、PHPStan L6 No errors、
unit 451 / integration 398 GREEN

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

.phpstan/stubs.php

@@ -0,0 +1,34 @@
+<?php
+/**
+ * PHPStan bootstrap stubs — plugin constants defined at runtime.
+ *
+ * PHPStan cannot see define()'d constants, so it reports "undefined constant"
+ * for every one of them. Stubbing them here keeps level 6 signal-to-noise high.
+ *
+ * TMDO_IS_SQLITE / TMDO_IS_MYSQL (and their WPDO_ aliases) are intentionally
+ * NOT stubbed to avoid literal-narrowing "always true/false" false positives
+ * on runtime-dynamic values.
+ *
+ * @package TMDO
+ */
+
+declare(strict_types=1);
+
+define( 'TMDO_VERSION', '0.0.0' );
+define( 'TMDO_DB_VERSION', '0.0.0' );
+define( 'TMDO_PATH', '/' );
+define( 'TMDO_URL', 'https://example.test/wp-content/plugins/2meet-data-optimizer/' );
+define( 'TMDO_FILE', '/2meet-data-optimizer.php' );
+define( 'TMDO_TABLE_PREFIX', 'wpdo_' );
+define( 'TMDO_CACHE_GROUP', 'wpdo' );
+define( 'TMDO_MIN_PHP', '8.1' );
+define( 'TMDO_MIN_WP', '6.0' );
+
+// Back-compat aliases exposed by class-tmdo-back-compat.php.
+define( 'WPDO_VERSION', '0.0.0' );
+define( 'WPDO_DB_VERSION', '0.0.0' );
+define( 'WPDO_PLUGIN_DIR', '/' );
+define( 'WPDO_PLUGIN_URL', 'https://example.test/wp-content/plugins/2meet-data-optimizer/' );
+define( 'WPDO_PLUGIN_FILE', '/2meet-data-optimizer.php' );
+define( 'WPDO_TABLE_PREFIX', 'wpdo_' );
+define( 'WPDO_CACHE_GROUP', 'wpdo' );