feat: 新增条件节点和多语言脚本支持

refactor(flow): 将Decision节点重命名为Condition节点
feat(flow): 新增多语言脚本执行器(Rhai/JS/Python)
feat(flow): 实现变量映射和执行功能
feat(flow): 添加条件节点执行逻辑
feat(frontend): 为开始/结束节点添加多语言描述
test: 添加yaml条件转换测试
chore: 移除废弃的storage模块

backend/src/flow/executors/script_js.rs

@@ -0,0 +1,54 @@
+use async_trait::async_trait;
+use serde_json::Value;
+use tracing::{debug, info};
+use std::time::Instant;
+
+use crate::flow::task::Executor;
+use crate::flow::domain::{NodeDef, NodeId};
+
+fn read_node_script_file(ctx: &Value, node_id: &str, lang_key: &str) -> Option<String> {
+    if let Some(nodes) = ctx.get("nodes").and_then(|v| v.as_object()) {
+        if let Some(m) = nodes.get(node_id).and_then(|v| v.get("scripts")).and_then(|v| v.as_object()) {
+            return m.get(lang_key).and_then(|v| v.as_str()).map(|s| s.to_string());
+        }
+    }
+    None
+}
+
+fn truncate_str(s: &str, max: usize) -> String {
+    let s = s.replace('\n', " ").replace('\r', " ");
+    if s.len() <= max { s } else { format!("{}…", &s[..max]) }
+}
+
+#[derive(Default)]
+pub struct ScriptJsTask;
+
+#[async_trait]
+impl Executor for ScriptJsTask {
+    async fn execute(&self, node_id: &NodeId, _node: &NodeDef, ctx: &mut Value) -> anyhow::Result<()> {
+        let start = Instant::now();
+
+        // 优先 nodes.<id>.scripts.js 指定的脚本文件路径
+        if let Some(path) = read_node_script_file(ctx, &node_id.0, "js") {
+            let preview = truncate_str(&path, 120);
+            info!(target = "udmin.flow", node=%node_id.0, file=%preview, "script_js task: JavaScript file execution not implemented yet (skipped)");
+            return Ok(());
+        }
+
+        // 兼容 inline 配置（暂不执行，仅提示）
+        let inline = ctx.get("script")
+            .or_else(|| ctx.get("expr"))
+            .and_then(|v| v.as_str())
+            .map(|s| s.to_string());
+        if let Some(code) = inline {
+            let preview = truncate_str(&code, 200);
+            debug!(target = "udmin.flow", node=%node_id.0, preview=%preview, "script_js task: inline script provided, but execution not implemented");
+            let _elapsed = start.elapsed().as_millis();
+            info!(target = "udmin.flow", node=%node_id.0, "script_js task: JavaScript execution not implemented yet (skipped)");
+            return Ok(());
+        }
+
+        info!(target = "udmin.flow", node=%node_id.0, "script_js task: no script found, skip");
+        Ok(())
+    }
+}