🏎️ perf: optimize aggregated model look-ups by batching bound-channel queries

Summary
-------
1. **Backend**
   • `model/model_meta.go`
     – Add `GetBoundChannelsForModels([]string)` to retrieve channels for multiple models in a single SQL (`IN (?)`) and deduplicate with `GROUP BY`.

   • `controller/model_meta.go`
     – In non-exact `fillModelExtra`:
       – Remove per-model `GetBoundChannels` calls.
       – Collect matched model names, then call `GetBoundChannelsForModels` once and merge results into `channelSet`.
       – Minor cleanup on loop logic; channel aggregation now happens after quota/group/endpoint processing.

Impact
------
• Eliminates N+1 query pattern for prefix/suffix/contains rules.
• Reduces DB round-trips from *N + 1* to **1**, markedly speeding up the model-management list load.
• Keeps existing `GetBoundChannels` API intact for single-model scenarios; no breaking changes.

model/model_meta.go

@@ -139,6 +139,21 @@ func GetBoundChannels(modelName string) ([]BoundChannel, error) {
 	return channels, err
 }
 
+// GetBoundChannelsForModels 批量查询多模型的绑定渠道并去重返回
+func GetBoundChannelsForModels(modelNames []string) ([]BoundChannel, error) {
+    if len(modelNames) == 0 {
+        return make([]BoundChannel, 0), nil
+    }
+    var channels []BoundChannel
+    err := DB.Table("channels").
+        Select("channels.name, channels.type").
+        Joins("join abilities on abilities.channel_id = channels.id").
+        Where("abilities.model IN ? AND abilities.enabled = ?", modelNames, true).
+        Group("channels.id").
+        Scan(&channels).Error
+    return channels, err
+}
+
 // FindModelByNameWithRule 根据模型名称和匹配规则查找模型元数据，优先级：精确 > 前缀 > 后缀 > 包含
 func FindModelByNameWithRule(name string) (*Model, error) {
 	// 1. 精确匹配