🚀 feat: expose “Enabled Groups” for models with real-time refresh

Backend
• model/model_meta.go
  – Added `EnableGroups []string` to Model struct
  – fillModelExtra now populates EnableGroups

• model/model_groups.go
  – New helper `GetModelEnableGroups` (reuses Pricing cache)

• model/pricing_refresh.go
  – Added `RefreshPricing()` to force immediate cache rebuild

• controller/model_meta.go
  – `GetAllModelsMeta` & `SearchModelsMeta` call `model.RefreshPricing()` before querying, ensuring groups / endpoints are up-to-date

Frontend
• ModelsColumnDefs.js
  – Added `renderGroups` util and “可用分组” table column displaying color-coded tags

Result
Admins can now see which user groups can access each model, and any ability/group changes are reflected instantly without the previous 1-minute delay.

model/pricing_refresh.go

@@ -0,0 +1,14 @@
+package model
+
+// RefreshPricing 强制立即重新计算与定价相关的缓存。
+// 该方法用于需要最新数据的内部管理 API，
+// 因此会绕过默认的 1 分钟延迟刷新。
+func RefreshPricing() {
+    updatePricingLock.Lock()
+    defer updatePricingLock.Unlock()
+
+    modelSupportEndpointsLock.Lock()
+    defer modelSupportEndpointsLock.Unlock()
+
+    updatePricing()
+}