fix(settings): sync enabled state after test passes

When test passes, props.model.enabled is updated but editingModel wasn't
synced, causing save button to remain disabled.

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

frontend/src/components/settings/LLMTableRow.vue

@@ -27,9 +27,15 @@ watch(() => props.isExpanded, (expanded, wasExpanded) => {
   }
 })
 
+// 当 test 通过后，props.model.enabled 会更新，需要同步到 editingModel
+watch(() => props.model.enabled, (enabled) => {
+  editingModel.value.enabled = enabled
+})
+
 const status = computed(() => {
-  if (!props.model.api_key || !props.model.model) return 'empty'
-  if (props.model.enabled) return 'available'
+  // 基于 editingModel 计算状态
+  if (!editingModel.value.api_key || !editingModel.value.model) return 'empty'
+  if (editingModel.value.enabled) return 'available'
   return 'unavailable'
 })