fix: parse ech-opts.config from Clash Meta YAML subscriptions

[xtgm]

Summary

Fixes #1115, Fixes #1131

The Clash YAML parser in RawUpdater.kt currently only reads ech-opts.enable but silently drops ech-opts.config. This causes ECH to be enabled without the actual ECH configuration data, making ECH non-functional for Clash Meta subscriptions.

The fix adds a "config" branch to the when block, storing the value in bean.echConfig.

The rest of the pipeline already works:

• StandardV2RayBean.java has the echConfig field
• V2RayFmt.kt (buildSingBoxOutboundTLS) already checks bean.echConfig.isNotBlank() and passes it to sing-box's OutboundECHOptions.config

Only RawUpdater.kt was missing the parsing step.

---

概要

修复 #1115、#1131

RawUpdater.kt 中的 Clash YAML 解析器目前只读取 ech-opts.enable，但丢弃了 ech-opts.config。这导致 ECH 虽然被启用，但没有实际的 ECH 配置数据，使得通过 Clash Meta 订阅导入的节点 ECH 功能无法生效。

修复方案：在 when 块中添加 "config" 分支，将值写入 bean.echConfig。

数据链路的其余部分已经正常工作：

• StandardV2RayBean.java 已有 echConfig 字段
• V2RayFmt.kt（buildSingBoxOutboundTLS）已正确检查 bean.echConfig.isNotBlank() 并传递给 sing-box 的 OutboundECHOptions.config

唯一缺失的就是 RawUpdater.kt 的解析步骤。

Changes

 "ech-opts" -> (opt.value as? Map<String, Any?>)?.also {
     for (echOpt in it) {
         when (echOpt.key) {
             "enable" -> bean.enableECH =
                 echOpt.value.toString() == "true"
+
+            "config" -> bean.echConfig =
+                echOpt.value?.toString() ?: ""
         }
     }
 }