fix(server): resolve latest available agent thread

server/internal/logic/lovart_agent_mapper.go

@@ -8,20 +8,24 @@ import (
 	"img_infinite_canvas/internal/types"
 )
 
-func latestLovartThreadID(project design.Project) string {
-	if threadID := strings.TrimSpace(project.LastThreadID); threadID != "" {
-		return threadID
-	}
-	for index := len(project.Messages) - 1; index >= 0; index-- {
-		message := project.Messages[index]
-		if isHiddenAgentMessage(message) {
+func latestLovartThreadID(currentThreadID string, threads []design.AgentThreadSummary) string {
+	currentThreadID = strings.TrimSpace(currentThreadID)
+	latestThreadID := ""
+	var latestTimestamp int64
+	for _, thread := range threads {
+		threadID := strings.TrimSpace(thread.AgentThreadID)
+		if threadID == "" {
 			continue
 		}
-		if threadID := strings.TrimSpace(message.ThreadID); threadID != "" {
+		if threadID == currentThreadID {
 			return threadID
 		}
+		if latestThreadID == "" || thread.UpdateTimestamp >= latestTimestamp {
+			latestThreadID = threadID
+			latestTimestamp = thread.UpdateTimestamp
+		}
 	}
-	return ""
+	return latestThreadID
 }
 
 func toCandaChatHistoryItem(message design.Message, projectID string, threadID string) types.CandaChatHistoryItem {