✨ feat: enhance model billing aggregation & UI display for unknown quota type

Summary
-------
1. **Backend**
   • `controller/model_meta.go`
     – For prefix/suffix/contains rules, aggregate endpoints, bound channels, enable groups, and quota types across all matched models.
     – When mixed billing types are detected, return `quota_type = -1` (unknown) instead of defaulting to volume-based.

2. **Frontend**
   • `web/src/helpers/utils.js`
     – `calculateModelPrice` now handles `quota_type = -1`, returning placeholder `'-'`.

   • `web/src/components/table/model-pricing/view/card/PricingCardView.jsx`
     – Billing tag logic updated: displays “按次计费” (times), “按量计费” (volume), or `'-'` for unknown.

   • `web/src/components/table/model-pricing/view/table/PricingTableColumns.js`
     – `renderQuotaType` shows “未知” for unknown billing type.

   • `web/src/components/table/models/ModelsColumnDefs.js`
     – Unified `renderQuotaType` to return `'-'` when type is unknown.

   • `web/src/components/table/model-pricing/modal/components/ModelPricingTable.jsx`
     – Group price table honors unknown billing type; pricing columns show `'-'` and neutral tag color.

3. **Utilities**
   • Added safe fallback colours/tags for unknown billing type across affected components.

Impact
------
• Ensures correct data aggregation for non-exact model matches.
• Prevents UI from implying volume billing when actual type is ambiguous.
• Provides consistent placeholder display (`'-'` or “未知”) across cards, tables and modals.

No breaking API changes; frontend gracefully handles legacy values.

web/src/components/table/model-pricing/view/card/PricingCardView.jsx

@@ -144,13 +144,24 @@ const PricingCardView = ({
   // 渲染标签
   const renderTags = (record) => {
     // 计费类型标签（左边）
-    const billingType = record.quota_type === 1 ? 'teal' : 'violet';
-    const billingText = record.quota_type === 1 ? t('按次计费') : t('按量计费');
-    const billingTag = (
-      <Tag key="billing" shape='circle' color={billingType} size='small'>
-        {billingText}
+    let billingTag = (
+      <Tag key="billing" shape='circle' color='white' size='small'>
+        -
       </Tag>
     );
+    if (record.quota_type === 1) {
+      billingTag = (
+        <Tag key="billing" shape='circle' color='teal' size='small'>
+          {t('按次计费')}
+        </Tag>
+      );
+    } else if (record.quota_type === 0) {
+      billingTag = (
+        <Tag key="billing" shape='circle' color='violet' size='small'>
+          {t('按量计费')}
+        </Tag>
+      );
+    }
 
     // 自定义标签（右边）
     const customTags = [];