refactor: remove add-rule button, keep only quick-add dropdown

All rule patterns are covered by presets, no need for blank rule creation

Also fix missing Refresh icon import

web/src/views/RiskRules.vue

@@ -54,7 +54,6 @@
       <!-- 右侧：卡片式可视化编辑 -->
       <div style="flex:1;overflow:auto;min-height:0">
         <div style="display:flex;gap:8px;align-items:center;margin-bottom:10px;flex-wrap:wrap">
-          <el-button size="small" type="primary" @click="addRule"><el-icon style="margin-right:2px"><Plus /></el-icon>添加规则</el-button>
           <el-dropdown @command="addPreset">
             <el-button size="small">快速添加<el-icon style="margin-left:2px"><ArrowDown /></el-icon></el-button>
             <template #dropdown>
@@ -69,7 +68,7 @@
               </el-dropdown-menu>
             </template>
           </el-dropdown>
-          <span v-if="!parsed.length" style="color:#909399;font-size:13px">— 暂无规则，点击添加或从模板导入</span>
+          <span v-if="!parsed.length" style="color:#909399;font-size:13px">— 暂无规则，请使用「快速添加」选择模板</span>
         </div>
 
         <!-- 规则卡片列表 -->
@@ -193,7 +192,7 @@
 
 <script setup>
 import { ref, computed, onMounted } from 'vue'
-import { Plus, ArrowDown, ArrowUp, Rank, Delete } from '@element-plus/icons-vue'
+import { ArrowDown, ArrowUp, Rank, Delete, Refresh } from '@element-plus/icons-vue'
 import api from '../api'
 
 // ============ 选项配置 ============
@@ -400,17 +399,6 @@ const editRule = async (row) => {
 
 const sync = () => { editorJson.value = JSON.stringify(parsed.value, null, 2) }
 
-const addRule = () => {
-  const d = typeDefaults['KILL']
-  const r = { type:'KILL', metric:d.metric, threshold:0, unit:d.unit, condition:d.condition,
-    applicable:null, description:'', _fold:false }
-  if (existsRule(r)) {
-    ElMessage.warning('活跃度（无条件）规则已存在，同类型+适用条件只能添加一次')
-    return
-  }
-  parsed.value = [...parsed.value, r]
-}
-
 const confirmRemove = async (idx) => {
   try { await ElMessageBox.confirm('确定删除此规则？', '确认', { type:'warning', confirmButtonText:'删除' }) } catch { return }
   const arr = [...parsed.value]; arr.splice(idx, 1); parsed.value = arr