fix: LLM 工具循环 400、中断消息注入、ConPTY 终端支持

- agent: 工具轮请求尾部补 user 占位(zen 网关强制),tool 消息正确配对
- agent: 工具提醒/中断以 system 角色注入并带 [中断消息] 前缀,不进用户履历;系统提示词说明中断消息格式
- agentcli: 基于 ConPTY 的交互式终端(ptywin fork),terminal_create/read/write/resize/close/watch
- webui: server 输出通道适配器(保留 reasoning_content/disable_thinking)
- GUI: 沉浸式标题栏、icon 圆角重制、mascot 等打磨

internal/plugins/cli/plugin.go

@@ -58,6 +58,14 @@ func (p *Plugin) Start(s *sdk.PluginSDK) error {
 		payload, _ := args["payload"].(string)
 		if payload != "" {
 			fmt.Println(payload)
+			s.Publish(&sdk.Event{
+				Type: sdk.EventAgentOutput,
+				Payload: map[string]interface{}{
+					"content": payload,
+					"channel": "cli",
+					"kind":    "channel_output",
+				},
+			})
 		}
 		return map[string]interface{}{"status": "ok"}, nil
 	})