feat: Agent 任务名与对话标题双能力自动生成

新增 task_auto_title_enabled / chat_auto_title_enabled（默认关）、
共享 GenerateAutoTitle、spawn_task 同步写 name、对话首条先截断再异步 AI，
设置页「自动标题」双 Switch。closes #55

server/server.go

@@ -3443,6 +3443,8 @@ func (s *Server) settingsPayload() map[string]any {
 		"traffic_capture":           s.m.TrafficEnabled(),
 		"agent_traffic_binding":     s.m.pg.GetBool(settingAgentTrafficBinding, false),
 		"task_intelligence_enabled": s.m.pg.GetBool(db.SettingTaskIntelligence, false),
+		db.SettingTaskAutoTitle:     s.m.pg.GetBool(db.SettingTaskAutoTitle, false),
+		db.SettingChatAutoTitle:     s.m.pg.GetBool(db.SettingChatAutoTitle, false),
 		db.SettingCredentialAgent:   s.m.pg.GetBool(db.SettingCredentialAgent, false),
 		db.SettingCredentialTraffic: s.m.pg.GetBool(db.SettingCredentialAgent, false) && s.m.pg.GetBool(db.SettingCredentialTraffic, false),
 		"llm_record":                s.m.LLMRecordEnabled(),
@@ -3517,6 +3519,8 @@ func (s *Server) putSettings(w http.ResponseWriter, r *http.Request) {
 		TrafficCapture      *bool `json:"traffic_capture"`
 		AgentTrafficBinding *bool `json:"agent_traffic_binding"`
 		TaskIntelligence    *bool `json:"task_intelligence_enabled"`
+		TaskAutoTitle       *bool `json:"task_auto_title_enabled"`
+		ChatAutoTitle       *bool `json:"chat_auto_title_enabled"`
 		CredentialAgent     *bool `json:"credential_agent_enabled"`
 		CredentialTraffic   *bool `json:"credential_traffic_binding"`
 		LLMRecord           *bool `json:"llm_record"` // LLM 录制开关（默认关）；即时生效，无需重建 agent
@@ -3689,6 +3693,18 @@ func (s *Server) putSettings(w http.ResponseWriter, r *http.Request) {
 			return
 		}
 	}
+	if req.TaskAutoTitle != nil {
+		if err := s.m.pg.SetBool(db.SettingTaskAutoTitle, *req.TaskAutoTitle); err != nil {
+			writeErr(w, 500, err.Error())
+			return
+		}
+	}
+	if req.ChatAutoTitle != nil {
+		if err := s.m.pg.SetBool(db.SettingChatAutoTitle, *req.ChatAutoTitle); err != nil {
+			writeErr(w, 500, err.Error())
+			return
+		}
+	}
 	if req.AgentTrafficBinding != nil {
 		if err := s.m.pg.SetBool(settingAgentTrafficBinding, *req.AgentTrafficBinding); err != nil {
 			writeErr(w, 500, err.Error())