refactor: 清理未使用代码并添加未来功能标记

style: 统一代码格式和注释风格

docs: 更新多个功能文档的完整度和状态

feat(runtime): 添加路径验证工具支持

fix(pipeline): 改进条件判断和变量解析逻辑

test(types): 为ID类型添加全面测试用例

chore: 更新依赖项和Cargo.lock文件

perf(mcp): 优化MCP协议传输和错误处理

crates/zclaw-pipeline/src/state.rs

@@ -7,7 +7,6 @@
 //! - Custom variables
 
 use std::collections::HashMap;
-use serde::{Deserialize, Serialize};
 use serde_json::Value;
 use regex::Regex;
 
@@ -156,7 +155,26 @@ impl ExecutionContext {
 
         match first {
             "inputs" => self.resolve_from_map(&self.inputs, rest, path),
-            "steps" => self.resolve_from_map(&self.steps_output, rest, path),
+            "steps" => {
+                // Handle "output" as a special key for step outputs
+                // steps.step_id.output.field -> steps_output["step_id"].field
+                // steps.step_id.field -> steps_output["step_id"].field (also supported)
+                if rest.len() >= 2 && rest[1] == "output" {
+                    // Skip "output" in the path: [step_id, "output", ...rest] -> [step_id, ...rest]
+                    let step_id = rest[0];
+                    let actual_rest = &rest[2..];
+                    let step_value = self.steps_output.get(step_id)
+                        .ok_or_else(|| StateError::VariableNotFound(step_id.to_string()))?;
+
+                    if actual_rest.is_empty() {
+                        Ok(step_value.clone())
+                    } else {
+                        self.resolve_from_value(step_value, actual_rest, path)
+                    }
+                } else {
+                    self.resolve_from_map(&self.steps_output, rest, path)
+                }
+            }
             "vars" | "var" => self.resolve_from_map(&self.variables, rest, path),
             "item" => {
                 if let Some(ctx) = &self.loop_context {