feat(llm): 任务 LLM 配置链改为任何状态都可修改

任务结束(done/failed/timeout)后主 Agent 对话仍走任务配置链,链上模型出问题时
既不能改配置链、也就没法继续交互。去掉 HTTP 与 DB 事务两处终态拦截,前端弹窗
对终态任务同样开放编辑与保存(顺带修掉 queued 状态也不能编辑的口子)。

终态任务保存时不再重开额度阻塞意图:那些意图会从 blocked 挪到 open,既没有
worker 执行、也不再满足「重跑意图」的可重跑条件,反而变成死状态。终态任务想
继续跑仍走重跑意图/新增目标,由它们把任务重新 admit 回运行态。

server/manager.go

@@ -935,8 +935,9 @@ func (m *Manager) DeleteCompanyWithAssets(id int64, deleteAssets bool) (int64, e
 	return assetsDeleted, nil
 }
 
-// ReplaceTaskLLMProfiles resets a non-terminal task's ordered provider chain and
-// mirrors the committed state onto the live task handle.
+// ReplaceTaskLLMProfiles resets a task's ordered provider chain and mirrors the
+// committed state onto the live task handle. Terminal tasks are editable too —
+// their 主 Agent 对话 keeps running on the chain after the task finishes.
 func (m *Manager) ReplaceTaskLLMProfiles(id string, profileIDs []int64, activeProfileID int64) (int64, error) {
 	n, err := strconv.ParseInt(id, 10, 64)
 	if err != nil {
@@ -954,6 +955,13 @@ func (m *Manager) ReplaceTaskLLMProfiles(id string, profileIDs []int64, activePr
 		task.setLLMState(pt.LLMProfileID, pt.ActiveLLMProfileID, pt.LLMProfileIDs, pt.LLMChainRevision, pt.LLMFailoverState, pt.LLMFailoverReason)
 	}
 	m.mu.Unlock()
+	// 终态任务不重开额度阻塞意图:任务已经没有 worker 在跑,重开只会把它们从
+	// blocked 挪到 open——那里既没人执行,也不再满足「重跑意图」的可重跑条件,
+	// 反而变成死状态。终态任务想接着跑,走重跑意图/新增目标,那条路会把任务重新
+	// admit 回运行态。
+	if pgdb.IsTerminal(pt.Status) {
+		return 0, nil
+	}
 	if task, ok := m.Task(id); ok {
 		reopened, reopenErr := task.Store.ReopenIntentsByBlockedReason(pgdb.IntentBlockedLLMQuota)
 		if reopenErr != nil {

server/server.go

@@ -1511,10 +1511,8 @@ func (s *Server) updateTaskLLMProfiles(w http.ResponseWriter, r *http.Request) {
 		writeErr(w, 404, "task not found")
 		return
 	}
-	if isTerminalStatus(t.lifecycleSnapshot().Status) {
-		writeErr(w, 409, "已结束的任务不能修改 LLM 配置")
-		return
-	}
+	// 任何生命周期状态(含终态)都可以改链:任务结束后主 Agent 对话仍走这条链,
+	// 模型不可用时不换链就等于把已完成任务的交互一起锁死。
 	before := t.llmStateSnapshot()
 	var req struct {
 		LLMProfileIDs      []int64 `json:"llm_profile_ids"`
@@ -1534,11 +1532,7 @@ func (s *Server) updateTaskLLMProfiles(w http.ResponseWriter, r *http.Request) {
 	}
 	reopened, err := s.m.ReplaceTaskLLMProfiles(t.ID, req.LLMProfileIDs, active)
 	if err != nil {
-		if strings.Contains(err.Error(), "terminal") {
-			writeErr(w, 409, err.Error())
-		} else {
-			writeErr(w, 400, err.Error())
-		}
+		writeErr(w, 400, err.Error())
 		return
 	}
 	// Profile edits affect only subsequent LLM calls. Existing in-flight calls