添加会话级固定预设

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

conversation/store.go

@@ -30,11 +30,16 @@ func (s *Store) path(id string) string {
 }
 
 func (s *Store) Create() (*message.Conversation, error) {
+	return s.CreateWithPreset("")
+}
+
+func (s *Store) CreateWithPreset(preset string) (*message.Conversation, error) {
 	conv := &message.Conversation{
-		ID:        utils.NewUUID(),
-		Title:     "新对话",
-		CreatedAt: time.Now(),
-		UpdatedAt: time.Now(),
+		ID:           utils.NewUUID(),
+		Title:        "新对话",
+		CreatedAt:    time.Now(),
+		UpdatedAt:    time.Now(),
+		PresetPrompt: strings.TrimSpace(preset),
 	}
 	if err := s.Save(conv); err != nil {
 		return nil, err
@@ -124,7 +129,7 @@ func SaveMessages(store *Store, id string, messages []message.ChatMessage, assis
 	if err != nil {
 		return err
 	}
-	conv.Messages = append([]message.ChatMessage(nil), messages...)
+	conv.Messages = filterPresetMessages(messages)
 	conv.Messages = append(conv.Messages, message.ChatMessage{Role: "assistant", Content: assistantContent})
 	if conv.Title == "" || conv.Title == "新对话" {
 		conv.Title = GenTitle(conv.Messages)
@@ -132,6 +137,17 @@ func SaveMessages(store *Store, id string, messages []message.ChatMessage, assis
 	return store.Save(conv)
 }
 
+func filterPresetMessages(messages []message.ChatMessage) []message.ChatMessage {
+	filtered := make([]message.ChatMessage, 0, len(messages))
+	for _, msg := range messages {
+		if msg.Hidden && strings.EqualFold(msg.Role, "system") {
+			continue
+		}
+		filtered = append(filtered, msg)
+	}
+	return filtered
+}
+
 func GenTitle(messages []message.ChatMessage) string {
 	for _, m := range messages {
 		if m.Hidden {