feat(tasks): 任务列表新增「运行中 Worker」列

TaskListMetricsAll 增加一个 LATERAL 子查询统计 kind='intent' 且
state='running' 的节点数，随 TaskDTO.in_flight 一并返回，口径与任务
详情页概览的「运行中 Worker」完全一致。列表页在「目标进度」后新增该
列，无运行中 Worker 时显示 0。

db/exploration.go

@@ -1064,9 +1064,10 @@ type GoalCounts struct{ Total, Met int }
 
 // TaskListMetrics contains the aggregates rendered in task lists.
 type TaskListMetrics struct {
-	Tokens       TokenUsage
+	Tokens         TokenUsage
-	LastActivity int64
+	LastActivity   int64
-	Goals        GoalCounts
+	Goals          GoalCounts
+	RunningIntents int // kind='intent' 且 state='running' 的条数，即运行中 Worker 数
 }
 
 // TaskListMetricsAll returns list aggregates for every live task in one query.
@@ -1081,7 +1082,8 @@ func (d *DB) TaskListMetricsAll() (map[int64]TaskListMetrics, error) {
 		       COALESCE(token_metrics.cache_write_tokens,0),
 		       COALESCE(latest_activity.created_at,0),
 		       COALESCE(goal_metrics.total,0),
-		       COALESCE(goal_metrics.met,0)
+		       COALESCE(goal_metrics.met,0),
+		       COALESCE(intent_metrics.running,0)
 		FROM tasks task
 		LEFT JOIN LATERAL (
 			SELECT SUM(input_tokens) AS input_tokens,
@@ -1104,6 +1106,11 @@ func (d *DB) TaskListMetricsAll() (map[int64]TaskListMetrics, error) {
 			FROM exploration_nodes
 			WHERE exploration_id=task.exploration_id AND kind='goal'
 		) goal_metrics ON true
+		LEFT JOIN LATERAL (
+			SELECT COUNT(*) AS running
+			FROM exploration_nodes
+			WHERE exploration_id=task.exploration_id AND kind='intent' AND state='running'
+		) intent_metrics ON true
 		WHERE task.deleted_at IS NULL`)
 	if err != nil {
 		return nil, err
@@ -1122,6 +1129,7 @@ func (d *DB) TaskListMetricsAll() (map[int64]TaskListMetrics, error) {
 			&metrics.LastActivity,
 			&metrics.Goals.Total,
 			&metrics.Goals.Met,
+			&metrics.RunningIntents,
 		); err != nil {
 			return nil, err
 		}

server/dto.go

@@ -50,6 +50,7 @@ type TaskDTO struct {
 	Tokens             TokenTotalDTO `json:"tokens"` // whole-task token consumption
 	GoalsTotal         int           `json:"goals_total"`
 	GoalsMet           int           `json:"goals_met"`
+	InFlight           int           `json:"in_flight"`                // 运行中 Worker 数（state=running 的意图）
 	LLMProfileID       *int64        `json:"llm_profile_id,omitempty"` // LLM profile used for this task; nil = default
 	LLMProfileIDs      []int64       `json:"llm_profile_ids"`
 	ActiveLLMProfileID *int64        `json:"active_llm_profile_id,omitempty"`

server/server.go

@@ -1064,6 +1064,7 @@ func (s *Server) listTasks(w http.ResponseWriter, r *http.Request) {
 		}
 		dto.GoalsTotal = metric.Goals.Total
 		dto.GoalsMet = metric.Goals.Met
+		dto.InFlight = metric.RunningIntents
 		dtos = append(dtos, dto)
 	}
 	writeJSON(w, 200, map[string]any{"tasks": dtos, "active": active})

web/src/app/(main)/function/tasks/page.tsx

@@ -948,6 +948,7 @@ export default function TasksPage() {
                       onSort={sortTasksBy}
                     />
                     <TableHead className="text-center">目标进度</TableHead>
+                    <TableHead className="text-center">运行中 Worker</TableHead>
                     <SortableTaskHead
                       field="created"
                       label="创建时间"
@@ -1210,6 +1211,13 @@ const TaskRow = React.memo(function TaskRow({
           <span className="text-muted-foreground">—</span>
         )}
       </TableCell>
+      <TableCell className="text-center text-xs tabular-nums">
+        {task.in_flight && task.in_flight > 0 ? (
+          <span className="text-foreground font-medium">{task.in_flight}</span>
+        ) : (
+          <span className="text-muted-foreground">0</span>
+        )}
+      </TableCell>
       <TableCell className="text-muted-foreground text-right text-xs whitespace-nowrap tabular-nums">
         {fmtDateTime(task.created_unix)}
       </TableCell>