修复多会话任务栏抖动、会话跳回与停止失效 (#264)

* fix(web): stabilize active task ordering

* fix(chat): preserve navigation during conversation startup

* fix(tasks): guarantee hard cancellation

* fix(chat): bind navigation and hard stop targets

* fix(chat): prevent replay from reclaiming navigation

internal/handler/task_manager.go

@@ -3,6 +3,7 @@ package handler
 import (
 	"context"
 	"errors"
+	"sort"
 	"strings"
 	"sync"
 	"time"
@@ -484,7 +485,10 @@ func (m *AgentTaskManager) CancelTask(conversationID string, cause error) (bool,
 	if runtimeCancel != nil {
 		runtimeHandled = runtimeCancel(cause)
 	}
-	if cancel != nil && !runtimeHandled {
+	// 「彻底停止」必须同时取消宿主 context：原生 Agent Cancel 即使已受理，
+	// 也可能只在安全点返回或报告超时，不能据此让整条任务继续存活。
+	// 中断并继续仍保留原语义：原生取消已处理时由运行时负责恢复。
+	if cancel != nil && (!runtimeHandled || errors.Is(cause, ErrTaskCancelled)) {
 		cancel(cause)
 	}
 	if toolCanceler != nil {
@@ -591,6 +595,12 @@ func (m *AgentTaskManager) GetActiveTasks() []*AgentTask {
 			Status:         task.Status,
 		})
 	}
+	sort.Slice(result, func(i, j int) bool {
+		if result[i].StartedAt.Equal(result[j].StartedAt) {
+			return result[i].ConversationID < result[j].ConversationID
+		}
+		return result[i].StartedAt.Before(result[j].StartedAt)
+	})
 	return result
 }
 

internal/handler/task_manager_order_test.go

@@ -0,0 +1,31 @@
+package handler
+
+import (
+	"testing"
+	"time"
+)
+
+func TestGetActiveTasksUsesStableCreationOrder(t *testing.T) {
+	m := NewAgentTaskManager()
+	started := time.Date(2026, 8, 19, 10, 0, 0, 0, time.UTC)
+	m.mu.Lock()
+	m.tasks = map[string]*AgentTask{
+		"conversation-z":    {ConversationID: "conversation-z", StartedAt: started, Status: "running"},
+		"conversation-late": {ConversationID: "conversation-late", StartedAt: started.Add(time.Minute), Status: "running"},
+		"conversation-a":    {ConversationID: "conversation-a", StartedAt: started, Status: "running"},
+	}
+	m.mu.Unlock()
+
+	want := []string{"conversation-a", "conversation-z", "conversation-late"}
+	for attempt := 0; attempt < 20; attempt++ {
+		gotTasks := m.GetActiveTasks()
+		if len(gotTasks) != len(want) {
+			t.Fatalf("GetActiveTasks() length = %d, want %d", len(gotTasks), len(want))
+		}
+		for i, task := range gotTasks {
+			if task.ConversationID != want[i] {
+				t.Fatalf("attempt %d order[%d] = %q, want %q", attempt, i, task.ConversationID, want[i])
+			}
+		}
+	}
+}

internal/handler/task_manager_tool_cancel_test.go

@@ -32,7 +32,7 @@ func TestCancelTaskInvokesToolCancelerOnFullStop(t *testing.T) {
 	}
 }
 
-func TestCancelTaskUsesAgentRuntimeCancelAsPrimaryPath(t *testing.T) {
+func TestCancelTaskFullStopCancelsRuntimeAndParentContext(t *testing.T) {
 	tm := NewAgentTaskManager()
 	var order []string
 	tm.SetToolCanceler(func(conversationID string) {
@@ -61,7 +61,7 @@ func TestCancelTaskUsesAgentRuntimeCancelAsPrimaryPath(t *testing.T) {
 	if err != nil || !ok {
 		t.Fatalf("CancelTask: ok=%v err=%v", ok, err)
 	}
-	want := []string{"runtime", "tool"}
+	want := []string{"runtime", "context", "tool"}
 	if len(order) != len(want) {
 		t.Fatalf("order length got %d want %d: %#v", len(order), len(want), order)
 	}
@@ -72,6 +72,29 @@ func TestCancelTaskUsesAgentRuntimeCancelAsPrimaryPath(t *testing.T) {
 	}
 }
 
+func TestCancelTaskInterruptContinueKeepsParentWhenRuntimeHandlesIt(t *testing.T) {
+	tm := NewAgentTaskManager()
+	ctx, cancel := context.WithCancelCause(context.Background())
+	if _, err := tm.StartTask("conv-interrupt-native", "hello", cancel); err != nil {
+		t.Fatalf("StartTask: %v", err)
+	}
+	unregister := tm.BindAgentRuntimeCancel("conv-interrupt-native", func(err error) bool {
+		if !errors.Is(err, multiagent.ErrInterruptContinue) {
+			t.Fatalf("runtime cancel got %v", err)
+		}
+		return true
+	})
+	defer unregister()
+
+	ok, err := tm.CancelTask("conv-interrupt-native", multiagent.ErrInterruptContinue)
+	if err != nil || !ok {
+		t.Fatalf("CancelTask: ok=%v err=%v", ok, err)
+	}
+	if cause := context.Cause(ctx); cause != nil {
+		t.Fatalf("interrupt-continue parent context cause = %v, want nil", cause)
+	}
+}
+
 func TestCancelTaskFallsBackToContextWhenAgentRuntimeCancelMisses(t *testing.T) {
 	tm := NewAgentTaskManager()
 	var order []string