feat(multi-agent): enable Director + butler delegation (Chunk 4)

- Enable multi-agent feature by default in desktop build
- Add butler delegation logic: task decomposition, expert assignment
- Add ExpertTask, DelegationResult, butler_delegate() to Director
- Add butler_delegate_task Tauri command bridging Director to frontend
- 13 Director tests passing (6 original + 7 new butler tests)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

crates/zclaw-kernel/src/director.rs

@@ -793,6 +793,246 @@ impl Default for DirectorBuilder {
     }
 }
 
+// ---------------------------------------------------------------------------
+// Butler delegation — task decomposition and expert assignment
+// ---------------------------------------------------------------------------
+
+/// A task assigned to an expert agent by the butler.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct ExpertTask {
+    /// Unique task ID
+    pub id: String,
+    /// The sub-task description
+    pub description: String,
+    /// Assigned expert agent (if any)
+    pub assigned_expert: Option<DirectorAgent>,
+    /// Task category (logistics, compliance, customer, pricing, technology, general)
+    pub category: String,
+    /// Task priority (higher = more urgent)
+    pub priority: u8,
+    /// Current status
+    pub status: ExpertTaskStatus,
+}
+
+/// Status of an expert task.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize, Default)]
+#[serde(rename_all = "snake_case")]
+pub enum ExpertTaskStatus {
+    #[default]
+    Pending,
+    Assigned,
+    InProgress,
+    Completed,
+    Failed,
+}
+
+/// Result of butler delegation.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct DelegationResult {
+    /// Original user request
+    pub request: String,
+    /// Decomposed sub-tasks with expert assignments
+    pub tasks: Vec<ExpertTask>,
+    /// Whether delegation was successful
+    pub success: bool,
+    /// Summary message for the user
+    pub summary: String,
+}
+
+impl Director {
+    /// Butler receives a user request, decomposes it into sub-tasks,
+    /// and assigns each to the best-matching registered expert agent.
+    ///
+    /// If no LLM driver is available, falls back to rule-based decomposition.
+    pub async fn butler_delegate(&self, user_request: &str) -> Result<DelegationResult> {
+        let agents = self.get_active_agents().await;
+
+        // Decompose the request into sub-tasks
+        let subtasks = if self.llm_driver.is_some() {
+            self.decompose_with_llm(user_request).await?
+        } else {
+            Self::decompose_rule_based(user_request)
+        };
+
+        // Assign experts to each sub-task
+        let tasks = self.assign_experts(&subtasks, &agents).await;
+
+        let summary = format!(
+            "已将您的需求拆解为 {} 个子任务{}。",
+            tasks.len(),
+            if tasks.iter().any(|t| t.assigned_expert.is_some()) {
+                "，已分派给对应专家"
+            } else {
+                ""
+            }
+        );
+
+        Ok(DelegationResult {
+            request: user_request.to_string(),
+            tasks,
+            success: true,
+            summary,
+        })
+    }
+
+    /// Use LLM to decompose a user request into structured sub-tasks.
+    async fn decompose_with_llm(&self, request: &str) -> Result<Vec<ExpertTask>> {
+        let driver = self.llm_driver.as_ref()
+            .ok_or_else(|| ZclawError::InvalidInput("No LLM driver configured".into()))?;
+
+        let prompt = format!(
+            r#"你是 ZCLAW 管家。请将以下用户需求拆解为 1-5 个具体子任务。
+
+用户需求：{}
+
+请按 JSON 数组格式输出，每个元素包含：
+- description: 子任务描述（中文）
+- category: 分类（logistics/compliance/customer/pricing/technology/general）
+- priority: 优先级 1-10
+
+只输出 JSON 数组，不要其他内容。"#,
+            request
+        );
+
+        let completion_request = CompletionRequest {
+            model: "default".to_string(),
+            system: Some("你是任务拆解专家，只输出 JSON。".to_string()),
+            messages: vec![zclaw_types::Message::User { content: prompt }],
+            tools: vec![],
+            max_tokens: Some(500),
+            temperature: Some(0.3),
+            stop: vec![],
+            stream: false,
+            thinking_enabled: false,
+            reasoning_effort: None,
+            plan_mode: false,
+        };
+
+        match driver.complete(completion_request).await {
+            Ok(response) => {
+                let text: String = response.content.iter()
+                    .filter_map(|block| match block {
+                        zclaw_runtime::ContentBlock::Text { text } => Some(text.as_str()),
+                        _ => None,
+                    })
+                    .collect::<Vec<_>>()
+                    .join("");
+
+                // Try to extract JSON array from response
+                let json_text = extract_json_array(&text);
+                match serde_json::from_str::<Vec<serde_json::Value>>(&json_text) {
+                    Ok(items) => {
+                        let tasks: Vec<ExpertTask> = items.into_iter().map(|item| {
+                            ExpertTask {
+                                id: uuid::Uuid::new_v4().to_string(),
+                                description: item.get("description")
+                                    .and_then(|v| v.as_str())
+                                    .unwrap_or("未命名任务")
+                                    .to_string(),
+                                assigned_expert: None,
+                                category: item.get("category")
+                                    .and_then(|v| v.as_str())
+                                    .unwrap_or("general")
+                                    .to_string(),
+                                priority: item.get("priority")
+                                    .and_then(|v| v.as_u64())
+                                    .unwrap_or(5) as u8,
+                                status: ExpertTaskStatus::Pending,
+                            }
+                        }).collect();
+                        Ok(tasks)
+                    }
+                    Err(_) => {
+                        // Fallback: treat the whole request as one task
+                        Ok(vec![ExpertTask {
+                            id: uuid::Uuid::new_v4().to_string(),
+                            description: request.to_string(),
+                            assigned_expert: None,
+                            category: "general".to_string(),
+                            priority: 5,
+                            status: ExpertTaskStatus::Pending,
+                        }])
+                    }
+                }
+            }
+            Err(e) => {
+                tracing::warn!("LLM decomposition failed: {}, falling back to rule-based", e);
+                Ok(Self::decompose_rule_based(request))
+            }
+        }
+    }
+
+    /// Rule-based decomposition for when no LLM is available.
+    fn decompose_rule_based(request: &str) -> Vec<ExpertTask> {
+        let category = classify_delegation_category(request);
+        vec![ExpertTask {
+            id: uuid::Uuid::new_v4().to_string(),
+            description: request.to_string(),
+            assigned_expert: None,
+            category,
+            priority: 5,
+            status: ExpertTaskStatus::Pending,
+        }]
+    }
+
+    /// Assign each task to the best-matching expert agent.
+    async fn assign_experts(
+        &self,
+        tasks: &[ExpertTask],
+        agents: &[DirectorAgent],
+    ) -> Vec<ExpertTask> {
+        tasks.iter().map(|task| {
+            let best_match = agents.iter().find(|agent| {
+                agent.role == AgentRole::Expert
+                    && agent.persona.to_lowercase().contains(&task.category.to_lowercase())
+            }).or_else(|| {
+                // Fallback: find any expert
+                agents.iter().find(|agent| agent.role == AgentRole::Expert)
+            });
+
+            let mut assigned = task.clone();
+            if let Some(expert) = best_match {
+                assigned.assigned_expert = Some(expert.clone());
+                assigned.status = ExpertTaskStatus::Assigned;
+            }
+            assigned
+        }).collect()
+    }
+}
+
+/// Classify a request into a delegation category based on keyword matching.
+fn classify_delegation_category(text: &str) -> String {
+    let lower = text.to_lowercase();
+    // Check compliance first — "合规/法规/标准" are more specific than logistics keywords
+    if ["合规", "法规", "标准", "认证", "报检"].iter().any(|k| lower.contains(k)) {
+        "compliance".to_string()
+    } else if ["物流", "发货", "出口", "包", "运输", "仓库"].iter().any(|k| lower.contains(k)) {
+        "logistics".to_string()
+    } else if ["客户", "投诉", "反馈", "服务", "售后"].iter().any(|k| lower.contains(k)) {
+        "customer".to_string()
+    } else if ["报价", "价格", "成本", "利润", "预算"].iter().any(|k| lower.contains(k)) {
+        "pricing".to_string()
+    } else if ["系统", "软件", "电脑", "网络", "数据"].iter().any(|k| lower.contains(k)) {
+        "technology".to_string()
+    } else {
+        "general".to_string()
+    }
+}
+
+/// Extract a JSON array from text that may contain surrounding prose.
+fn extract_json_array(text: &str) -> String {
+    // Try to find content between [ and ]
+    if let Some(start) = text.find('[') {
+        if let Some(end) = text.rfind(']') {
+            if end > start {
+                return text[start..=end].to_string();
+            }
+        }
+    }
+    // Return original if no array brackets found
+    text.to_string()
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -912,4 +1152,88 @@ mod tests {
         assert_eq!(AgentRole::from_str("STUDENT"), Some(AgentRole::Student));
         assert_eq!(AgentRole::from_str("unknown"), None);
     }
+
+    // -- Butler delegation tests --
+
+    #[test]
+    fn test_classify_delegation_category() {
+        assert_eq!(classify_delegation_category("这批物流要发往欧洲"), "logistics");
+        assert_eq!(classify_delegation_category("出口合规标准变了"), "compliance");
+        assert_eq!(classify_delegation_category("客户投诉太多了"), "customer");
+        assert_eq!(classify_delegation_category("报价需要调整"), "pricing");
+        assert_eq!(classify_delegation_category("系统又崩了"), "technology");
+        assert_eq!(classify_delegation_category("随便聊聊"), "general");
+    }
+
+    #[test]
+    fn test_extract_json_array() {
+        let with_prose = "好的，分析如下：\n[{\"description\":\"分析物流\",\"category\":\"logistics\",\"priority\":8}]\n以上。";
+        let result = extract_json_array(with_prose);
+        assert!(result.starts_with('['));
+        assert!(result.ends_with(']'));
+
+        let bare = "[{\"a\":1}]";
+        assert_eq!(extract_json_array(bare), bare);
+
+        let no_array = "just text";
+        assert_eq!(extract_json_array(no_array), "just text");
+    }
+
+    #[tokio::test]
+    async fn test_rule_based_decomposition() {
+        let tasks = Director::decompose_rule_based("出口包装需要整改");
+        assert_eq!(tasks.len(), 1);
+        // "包" matches logistics first
+        assert_eq!(tasks[0].category, "logistics");
+        assert_eq!(tasks[0].status, ExpertTaskStatus::Pending);
+        assert!(!tasks[0].id.is_empty());
+    }
+
+    #[tokio::test]
+    async fn test_butler_delegate_rule_based() {
+        let director = Director::new(DirectorConfig::default());
+
+        // Register an expert
+        director.register_agent(DirectorAgent::new(
+            AgentId::new(),
+            "合规专家",
+            AgentRole::Expert,
+            "擅长 compliance 和 logistics 领域",
+        )).await;
+
+        let result = director.butler_delegate("出口包装被退回了，需要整改").await.unwrap();
+        assert!(result.success);
+        assert!(result.summary.contains("拆解为"));
+        assert_eq!(result.tasks.len(), 1);
+        // Expert should be assigned (matches category)
+        assert!(result.tasks[0].assigned_expert.is_some());
+        assert_eq!(result.tasks[0].status, ExpertTaskStatus::Assigned);
+    }
+
+    #[tokio::test]
+    async fn test_butler_delegate_no_experts() {
+        let director = Director::new(DirectorConfig::default());
+        // No agents registered
+        let result = director.butler_delegate("帮我查一下物流状态").await.unwrap();
+        assert!(result.success);
+        assert!(result.tasks[0].assigned_expert.is_none());
+        assert_eq!(result.tasks[0].status, ExpertTaskStatus::Pending);
+    }
+
+    #[test]
+    fn test_expert_task_serialization() {
+        let task = ExpertTask {
+            id: "test-id".to_string(),
+            description: "测试任务".to_string(),
+            assigned_expert: None,
+            category: "logistics".to_string(),
+            priority: 8,
+            status: ExpertTaskStatus::Assigned,
+        };
+        let json = serde_json::to_string(&task).unwrap();
+        let decoded: ExpertTask = serde_json::from_str(&json).unwrap();
+        assert_eq!(decoded.id, "test-id");
+        assert_eq!(decoded.category, "logistics");
+        assert_eq!(decoded.status, ExpertTaskStatus::Assigned);
+    }
 }