feat(host-agent): persist OCR/UI overlay toggle preference

Save the "Show OCR/UI-tree bounding boxes" checkbox state to localStorage so it persists across page refreshes in the task detail view.

apps/device-host-agent/host_agent/web/templates/task_detail.html

@@ -225,9 +225,24 @@
 
       const toggle = document.getElementById("overlay-boxes-toggle");
       if (toggle) {
-        toggle.addEventListener("change", function () {
+        const STORAGE_KEY = "task-detail-overlay-boxes-visible";
+        
+        // 页面加载时恢复之前的选择
+        const savedState = localStorage.getItem(STORAGE_KEY);
+        if (savedState !== null) {
+          const shouldShow = savedState === "true";
+          toggle.checked = shouldShow;
           document.querySelectorAll("svg.overlay-svg").forEach(function (svg) {
-            svg.classList.toggle("show-boxes", toggle.checked);
+            svg.classList.toggle("show-boxes", shouldShow);
+          });
+        }
+        
+        toggle.addEventListener("change", function () {
+          const isChecked = toggle.checked;
+          // 保存状态到 localStorage
+          localStorage.setItem(STORAGE_KEY, String(isChecked));
+          document.querySelectorAll("svg.overlay-svg").forEach(function (svg) {
+            svg.classList.toggle("show-boxes", isChecked);
           });
         });
       }