feat(ui): 画面 Tab 刷新机制由自动改为手动

kotonebot/kaa/main/gr.py

@@ -1504,6 +1504,7 @@ class KotoneBotUI:
     def _create_screen_tab(self) -> None:
         with gr.Tab("画面"):
             gr.Markdown("## 当前设备画面")
+            refresh_btn = gr.Button("刷新画面", variant="primary")
             WIDTH = 720 // 3
             HEIGHT = 1280 // 3
             last_update_text = gr.Markdown("上次更新时间：无数据")
@@ -1512,14 +1513,14 @@ class KotoneBotUI:
             def update_screenshot():
                 ctx = ContextStackVars.current()
                 if ctx is None:
-                    return [None, last_update_text.value]
+                    return [None, "上次更新时间：无上下文数据"]
                 screenshot = ctx._screenshot
                 if screenshot is None:
-                    return [None, last_update_text.value]
+                    return [None, "上次更新时间：无截图数据"]
                 screenshot = cv2.cvtColor(screenshot, cv2.COLOR_BGR2RGB)
                 return screenshot, f"上次更新时间：{datetime.now().strftime('%Y-%m-%d %H:%M:%S')}"
 
-            gr.Timer(0.3).tick(
+            refresh_btn.click(
                 fn=update_screenshot,
                 outputs=[screenshot_display, last_update_text]
             )