feat(mcp): MCP 密钥管理后台（CURD 重组 Base/App，密钥仅创建时明文展示）

database/migrations/20260816203003_system_mcp_log.php

@@ -0,0 +1,25 @@
+<?php
+
+use think\migration\Migrator;
+
+class SystemMcpLog extends Migrator
+{
+    /**
+     * MCP调用日志表.
+     *
+     * 仅 create_time（写入后不变），无 update_time / delete_time。
+     */
+    public function change()
+    {
+        $table = $this->table('system_mcp_log')
+            ->setComment('MCP调用日志表')
+            ->addColumn('key_id', 'biginteger', ['limit' => 11, 'null' => true, 'signed' => false, 'comment' => '密钥ID'])
+            ->addColumn('node', 'char', ['limit' => 100, 'null' => true, 'comment' => '调用节点'])
+            ->addColumn('arguments', 'text', ['null' => true, 'comment' => '参数摘要JSON'])
+            ->addColumn('is_success', 'integer', ['limit' => 1, 'null' => true, 'default' => 1, 'comment' => '是否成功:0=失败,1=成功'])
+            ->addColumn('cost_ms', 'integer', ['limit' => 11, 'null' => true, 'default' => 0, 'comment' => '耗时毫秒'])
+            ->addColumn('create_time', 'integer', ['limit' => 11, 'null' => true, 'default' => 0, 'signed' => false, 'comment' => '创建时间'])
+            ->addIndex(['key_id'], ['name' => 'key_id'])
+            ->create();
+    }
+}