功能：ROI绑定算法时校验RTSP地址有效性

截图加载失败时阻止算法绑定并提示"RTSP拉流地址无效"，
通过Canvas截图加载状态逐层传递到算法绑定组件实现校验。

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/web-antd/src/views/aiot/device/roi/index.vue

@@ -64,6 +64,7 @@ const roiList = ref<AiotDeviceApi.Roi[]>([]);
 const selectedRoiId = ref<null | string>(null);
 const selectedRoiBindings = ref<AiotDeviceApi.RoiAlgoBinding[]>([]);
 const snapUrl = ref('');
+const snapOk = ref(false);
 
 const edgeDevices = ref<Array<{ deviceId: string }>>([]);
 
@@ -157,6 +158,10 @@ async function refreshSnap() {
   await buildSnapUrl(true);
 }
 
+function onSnapStatus(ok: boolean) {
+  snapOk.value = ok;
+}
+
 // ==================== ROI 数据加载 ====================
 
 async function loadRois() {
@@ -352,6 +357,7 @@ function handlePush() {
             @roi-drawn="onRoiDrawn"
             @roi-selected="onRoiSelected"
             @roi-deleted="onRoiDeleted"
+            @snap-status="onSnapStatus"
           />
         </div>
 
@@ -471,6 +477,7 @@ function handlePush() {
             <RoiAlgorithmBind
               :roi-id="selectedRoi.roiId || ''"
               :bindings="selectedRoiBindings"
+              :snap-ok="snapOk"
               @changed="loadRoiDetail"
             />
           </div>