fix(agent): add TargetRef nil guards and ensureHistory for robustness

- Add nil checks for session.TargetRef in all four execute*Action
  handlers (Trader/Exchange/Model/Strategy) to prevent panic on
  corrupted sessions; bulk-delete and query actions are excluded
- Add ensureHistory() helper and call it in runPlannedAgentWithContextMode
  to prevent nil panic when history is not initialized

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

agent/agent.go

@@ -80,6 +80,12 @@ func New(tm *manager.TraderManager, st *store.Store, cfg *Config, logger *slog.L
 
 func (a *Agent) SetAIClient(c mcp.AIClient) { a.aiClient = c }
 
+func (a *Agent) ensureHistory() {
+	if a.history == nil {
+		a.history = newChatHistory(100)
+	}
+}
+
 func (a *Agent) log() *slog.Logger {
 	if a != nil && a.logger != nil {
 		return a.logger

agent/planner_runtime.go

@@ -2551,6 +2551,7 @@ func (a *Agent) runPlannedAgentWithContextMode(ctx context.Context, storeUserID
 		answer, _, err := a.driveActiveSession(ctx, storeUserID, userID, lang, text, session, onEvent)
 		return answer, err
 	}
+	a.ensureHistory()
 	a.history.Add(userID, "user", text)
 	if onEvent != nil {
 		onEvent(StreamEventPlanning, a.planningStatusText(lang))

agent/skill_execution_handlers.go

@@ -1479,6 +1479,12 @@ func (a *Agent) executeTraderManagementAction(storeUserID string, userID int64,
 		}
 		return formatReadFastPathResponse(lang, "list_traders", a.toolListTraders(storeUserID))
 	case "start", "stop", "delete":
+		if session.TargetRef == nil && !(session.Action == "delete" && fieldValue(session, "bulk_scope") == "all") {
+			if lang == "zh" {
+				return "请先指定要操作的交易员。"
+			}
+			return "Please specify which trader to operate on."
+		}
 		if fieldValue(session, skillDAGStepField) == "" {
 			setSkillDAGStep(&session, "await_confirmation")
 		}
@@ -1894,6 +1900,17 @@ func (a *Agent) executeBulkTraderDelete(storeUserID string, userID int64, lang,
 }
 
 func (a *Agent) executeExchangeManagementAction(storeUserID string, userID int64, lang, text string, session skillSession) string {
+	switch session.Action {
+	case "query", "query_list", "create":
+		// These actions don't need a target — fall through.
+	default:
+		if session.TargetRef == nil {
+			if lang == "zh" {
+				return "请先指定要操作的交易所配置。"
+			}
+			return "Please specify which exchange config to operate on."
+		}
+	}
 	switch session.Action {
 	case "query_detail":
 		if detail, ok := a.describeExchange(storeUserID, lang, session.TargetRef); ok {
@@ -2069,6 +2086,17 @@ func (a *Agent) executeExchangeManagementAction(storeUserID string, userID int64
 }
 
 func (a *Agent) executeModelManagementAction(storeUserID string, userID int64, lang, text string, session skillSession) string {
+	switch session.Action {
+	case "query", "query_list", "create":
+		// These actions don't need a target — fall through.
+	default:
+		if session.TargetRef == nil {
+			if lang == "zh" {
+				return "请先指定要操作的模型。"
+			}
+			return "Please specify which model to operate on."
+		}
+	}
 	switch session.Action {
 	case "query_detail":
 		if detail, ok := a.describeModel(storeUserID, lang, session.TargetRef); ok {
@@ -2228,6 +2256,18 @@ func (a *Agent) executeModelManagementAction(storeUserID string, userID int64, l
 }
 
 func (a *Agent) executeStrategyManagementAction(storeUserID string, userID int64, lang, text string, session skillSession) string {
+	switch session.Action {
+	case "query", "query_list", "create":
+		// These actions don't need a target — fall through.
+	default:
+		isBulkDelete := session.Action == "delete" && fieldValue(session, "bulk_scope") == "all"
+		if session.TargetRef == nil && !isBulkDelete {
+			if lang == "zh" {
+				return "请先指定要操作的策略。"
+			}
+			return "Please specify which strategy to operate on."
+		}
+	}
 	switch session.Action {
 	case "query", "query_list":
 		return formatReadFastPathResponse(lang, "get_strategies", a.toolGetStrategies(storeUserID))