refactor(subagent): 支持带类型的子智能体标题格式

- 将子智能体标题解析升级为支持 "Subagent [type]: description" 格式
- 兼容旧格式 "Subagent: description"，默认类型为 "general"
- 修改子智能体会话标题生成，包含类型信息
- 优化记录解析和会话创建逻辑，提高子智能体信息表达准确性

src/command/handlers/load_task_messages.rs

@@ -144,12 +144,8 @@ fn reconstruct_task_from_db(
         })
         .unwrap_or_default();
 
-    // Extract description from title: "Subagent: {description}"
-    let description = record
-        .title
-        .strip_prefix("Subagent: ")
-        .unwrap_or(&record.title)
-        .to_string();
+    // Extract subagent_type and description from title
+    let (subagent_type, description) = parse_subagent_title(&record.title);
 
     let now = record.updated_at;
 
@@ -161,7 +157,7 @@ fn reconstruct_task_from_db(
         parent_chat_id: record.chat_id.clone(),
         parent_channel_name: record.channel_name.clone(),
         description,
-        subagent_type: "general".to_string(),
+        subagent_type,
         state: TaskSessionState::Completed,
         created_at: record.created_at,
         updated_at: now,
@@ -169,3 +165,18 @@ fn reconstruct_task_from_db(
         error: None,
     }))
 }
+
+/// Parse subagent title to extract type and description.
+/// New format: "Subagent [type]: description"
+/// Legacy format: "Subagent: description" (defaults to "general")
+fn parse_subagent_title(title: &str) -> (String, String) {
+    if let Some(rest) = title.strip_prefix("Subagent [") {
+        if let Some(bracket_pos) = rest.find("]: ") {
+            let agent_type = rest[..bracket_pos].to_string();
+            let desc = rest[bracket_pos + 3..].to_string();
+            return (agent_type, desc);
+        }
+    }
+    let desc = title.strip_prefix("Subagent: ").unwrap_or(title).to_string();
+    ("general".to_string(), desc)
+}

src/tools/task/runtime.rs

@@ -509,7 +509,7 @@ impl SubAgentRuntime for DefaultSubAgentRuntime {
         );
 
         // 4. 在 sessions 表中创建子智能体会话（确保外键约束满足）
-        let session_title = format!("Subagent: {}", task.description);
+        let session_title = format!("Subagent [{}]: {}", session.subagent_type, task.description);
         if let Err(e) = self.conversation_repository.ensure_session(
             &session.session_id,
             &session.parent_channel_name,
@@ -638,7 +638,7 @@ impl SubAgentRuntime for DefaultSubAgentRuntime {
         }
 
         // 3. 确保 sessions 表中存在子智能体会话记录
-        let session_title = format!("Subagent: {}", session.description);
+        let session_title = format!("Subagent [{}]: {}", session.subagent_type, session.description);
         if let Err(e) = self.conversation_repository.ensure_session(
             &session.session_id,
             &session.parent_channel_name,