feat(ui): 设置页重设计 + 全站表格配色统一为亮色变量

- 设置页：移除暗色残留，统一页头/卡片/图标块/按钮样式
- 模型管理：照 vivid 重排——模型名等宽显示，子行展示渠道名+权重，
  定价胶囊「档位+普通价+代理价」，配置列统一灰色等宽标签，
  操作列加宽修复删除按钮被挤
- 后端 ModelsView 返回每个模型绑定的渠道名列表（channel_models JOIN）
- 全站 scoped 样式里的硬编码白值(rgb(255 255 255/white)批量替换为
  主题变量，修复亮色模式下表头/开关/操作按钮不可见（如渠道表头）
- 关于页：联系卡片统一等高布局，链接/非链接卡片对齐一致

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

backend/internal/repo/channel_repo.go

@@ -183,6 +183,26 @@ func (r *ChannelRepository) RoutableModelIDs(ctx context.Context) (map[string]st
 	return out, err
 }
 
+// ChannelNamesByModel returns model_id -> bound channel display names in one
+// JOIN query — used by the admin models table to annotate each row with the
+// channel(s) it was synced from.
+func (r *ChannelRepository) ChannelNamesByModel(ctx context.Context) (map[string][]string, error) {
+	var rows []struct {
+		ModelID string `gorm:"column:model_id"`
+		Name    string `gorm:"column:name"`
+	}
+	err := r.db.WithContext(ctx).
+		Table("channel_models").
+		Select("channel_models.model_id, channels.name").
+		Joins("JOIN channels ON channels.id = channel_models.channel_id").
+		Scan(&rows).Error
+	out := make(map[string][]string, len(rows))
+	for _, row := range rows {
+		out[row.ModelID] = append(out[row.ModelID], row.Name)
+	}
+	return out, err
+}
+
 // ChannelIDsByModel lists channel ids bound to a model (any enabled state).
 func (r *ChannelRepository) ChannelIDsByModel(ctx context.Context, modelID string) ([]string, error) {
 	var ids []string