feat: 支持工作流插件复用与试运行

- 新增工作流插件类型、发布快照同步、实时可用性与下线影响检查

- 收口绑定候选、分类权限、间接环路校验与运行态优雅降级

- 补齐管理端工作流插件配置、详情与试运行界面及定向测试

easyflow-starter/easyflow-starter-all/src/main/resources/db/migration/mysql/V10__mysql_workflow_plugin_schema_hash_patch.sql

@@ -0,0 +1,2 @@
+ALTER TABLE tb_plugin_item
+    ADD COLUMN schema_hash varchar(128) NULL COMMENT '工作流插件输入输出契约哈希' AFTER english_name;

easyflow-starter/easyflow-starter-all/src/main/resources/db/migration/mysql/V9__mysql_workflow_plugin_patch.sql

@@ -0,0 +1,8 @@
+ALTER TABLE `tb_plugin`
+    ADD COLUMN `workflow_id` bigint NULL DEFAULT NULL COMMENT '绑定工作流ID' AFTER `type`;
+
+UPDATE `tb_plugin`
+SET `type` = 1
+WHERE `type` IS NULL;
+
+CREATE INDEX `idx_tb_plugin_workflow_id` ON `tb_plugin` (`workflow_id`);