refactor: 评测列表移除内嵌维度管理

EvalView 移除维度列表加载/删除与相关 Tab 内容，聚焦评测任务展示；维度表单与规则步骤同步微调，回归脚本适配。

frontend/src/views/eval/create/DimensionFormFields.vue

@@ -21,7 +21,15 @@ export interface DimensionFormDraft {
   pass_threshold: number
 }
 
-defineProps<{ evalModels: ModelItem[] }>()
+withDefaults(
+  defineProps<{
+    evalModels: ModelItem[]
+    showDescription?: boolean
+  }>(),
+  {
+    showDescription: true,
+  },
+)
 
 const form = defineModel<DimensionFormDraft>({ required: true })
 
@@ -66,7 +74,7 @@ watch(
     </el-select>
   </el-form-item>
 
-  <el-form-item label="描述">
+  <el-form-item v-if="showDescription" label="描述">
     <el-input v-model="form.description" type="textarea" :rows="2" maxlength="200" show-word-limit />
   </el-form-item>
 

frontend/src/views/eval/create/EvalRuleSetupStep.vue

@@ -63,7 +63,11 @@ defineExpose({ validate })
       :disabled="disabled"
       scroll-to-error
     >
-      <DimensionFormFields v-model="form.newDimension" :eval-models="evalModels" />
+      <DimensionFormFields
+        v-model="form.newDimension"
+        :eval-models="evalModels"
+        :show-description="false"
+      />
     </el-form>
   </div>
 </template>