feat(group): 添加分组级别模型路由配置功能

支持为分组配置模型路由规则，可以指定特定模型模式优先使用的账号列表。

  - 新增 model_routing 字段存储路由配置（JSONB格式，支持通配符匹配）

  - 新增 model_routing_enabled 字段控制是否启用路由

  - 更新后端 handler/service/repository 支持路由配置的增删改查

  - 更新前端 GroupsView 添加路由配置界面

  - 添加数据库迁移脚本 040/041

backend/ent/group/where.go

@@ -150,6 +150,11 @@ func FallbackGroupID(v int64) predicate.Group {
 	return predicate.Group(sql.FieldEQ(FieldFallbackGroupID, v))
 }
 
+// ModelRoutingEnabled applies equality check predicate on the "model_routing_enabled" field. It's identical to ModelRoutingEnabledEQ.
+func ModelRoutingEnabled(v bool) predicate.Group {
+	return predicate.Group(sql.FieldEQ(FieldModelRoutingEnabled, v))
+}
+
 // CreatedAtEQ applies the EQ predicate on the "created_at" field.
 func CreatedAtEQ(v time.Time) predicate.Group {
 	return predicate.Group(sql.FieldEQ(FieldCreatedAt, v))
@@ -1065,6 +1070,26 @@ func FallbackGroupIDNotNil() predicate.Group {
 	return predicate.Group(sql.FieldNotNull(FieldFallbackGroupID))
 }
 
+// ModelRoutingIsNil applies the IsNil predicate on the "model_routing" field.
+func ModelRoutingIsNil() predicate.Group {
+	return predicate.Group(sql.FieldIsNull(FieldModelRouting))
+}
+
+// ModelRoutingNotNil applies the NotNil predicate on the "model_routing" field.
+func ModelRoutingNotNil() predicate.Group {
+	return predicate.Group(sql.FieldNotNull(FieldModelRouting))
+}
+
+// ModelRoutingEnabledEQ applies the EQ predicate on the "model_routing_enabled" field.
+func ModelRoutingEnabledEQ(v bool) predicate.Group {
+	return predicate.Group(sql.FieldEQ(FieldModelRoutingEnabled, v))
+}
+
+// ModelRoutingEnabledNEQ applies the NEQ predicate on the "model_routing_enabled" field.
+func ModelRoutingEnabledNEQ(v bool) predicate.Group {
+	return predicate.Group(sql.FieldNEQ(FieldModelRoutingEnabled, v))
+}
+
 // HasAPIKeys applies the HasEdge predicate on the "api_keys" edge.
 func HasAPIKeys() predicate.Group {
 	return predicate.Group(func(s *sql.Selector) {