✨ feat: Add model icon support across backend and UI; prefer model icon over vendor; add icon column in Models table

Backend:
- Model: Add `icon` field to `model.Model` (gorm: varchar(128)); auto-migrated via GORM.
- Pricing API: Extend `model.Pricing` with `icon` and populate from model meta in `GetPricing()`.

Frontend:
- EditModelModal: Add `icon` input (with @lobehub/icons helper link); wire into init/load/submit flows.
- ModelHeader / PricingCardView: Prefer rendering `model.icon`; fallback to `vendor_icon`; final fallback to initials avatar.
- Models table: Add leading “Icon” column, rendering `model.icon` or `vendor` icon via `getLobeHubIcon`.

Notes:
- Backward-compatible. Existing data without `icon` remain unaffected.
- No manual SQL needed; column is added by AutoMigrate.

Affected files:
- model/model_meta.go
- model/pricing.go
- web/src/components/table/models/modals/EditModelModal.jsx
- web/src/components/table/model-pricing/modal/components/ModelHeader.jsx
- web/src/components/table/model-pricing/view/card/PricingCardView.jsx
- web/src/components/table/models/ModelsColumnDefs.js

web/src/components/table/models/ModelsColumnDefs.js

@@ -33,6 +33,17 @@ function renderTimestamp(timestamp) {
   return <>{timestamp2string(timestamp)}</>;
 }
 
+// Render model icon column: prefer model.icon, then fallback to vendor icon
+const renderModelIconCol = (record, vendorMap) => {
+  const iconKey = record?.icon || vendorMap[record?.vendor_id]?.icon;
+  if (!iconKey) return '-';
+  return (
+    <div className="flex items-center justify-center">
+      {getLobeHubIcon(iconKey, 20)}
+    </div>
+  );
+};
+
 // Render vendor column with icon
 const renderVendorTag = (vendorId, vendorMap, t) => {
   if (!vendorId || !vendorMap[vendorId]) return '-';
@@ -222,6 +233,13 @@ export const getModelsColumns = ({
   vendorMap,
 }) => {
   return [
+    {
+      title: t('图标'),
+      dataIndex: 'icon',
+      width: 70,
+      align: 'center',
+      render: (text, record) => renderModelIconCol(record, vendorMap),
+    },
     {
       title: t('模型名称'),
       dataIndex: 'model_name',