{
  "id": "m0002",
  "title": "建 pipeline_agent_instances 表（poller 实例 id 机制，9/1 修复 1406/审计根因）",
  "backup_tables": [],
  "up": [
    {"op": "sql", "sql": "CREATE TABLE IF NOT EXISTS pipeline_agent_instances (id VARCHAR(32) NOT NULL COMMENT '主键ID', project_id VARCHAR(32) NOT NULL DEFAULT '' COMMENT '项目ID', role VARCHAR(64) NOT NULL COMMENT '角色(agent.xxx)', agent_id VARCHAR(32) NOT NULL COMMENT '实例ID(ag.xxxx)', status VARCHAR(16) NOT NULL DEFAULT 'active' COMMENT '状态', created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP NOT NULL COMMENT '创建时间', updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP NOT NULL COMMENT '更新时间', PRIMARY KEY(id)) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci engine=innodb COMMENT '角色agent实例注册(项目×角色→稳定实例id)'"},
    {"op": "sql", "sql": "CREATE UNIQUE INDEX pipeline_agent_instances_idx_pai_pr ON pipeline_agent_instances(project_id, role)"}
  ],
  "down": [
    {"op": "sql", "sql": "DROP TABLE pipeline_agent_instances"}
  ]
}