feat(sub): make the host "Mihomo X25519" switch drop ML-KEM (#6803)

The per-host Mihomo X25519 switch has been stored since managed hosts landed,
but no renderer read it, while every REALITY proxy was forced to
support-x25519mlkem768: true. On some networks DPI drops the second segment of
an ML-KEM ClientHello and blackholes the server for that client. A host with the
switch on now gets support-x25519mlkem768: false and no ML-KEM hint in its vless
link; switches saved while they had no effect are cleared once, so upgrading
does not silently change existing subscriptions.

A REALITY host's fingerprint now reaches the Clash and JSON outputs, and every
host endpoint gets its own deep copy of the stream, so one host's blank SNI,
fingerprint, Host header or path no longer inherits another host's value.

internal/web/translation/zh-TW.json

@@ -2383,6 +2383,7 @@
         "serverDescription": "顯示於備註下方的選填註記。",
         "allowInsecure": "略過 TLS 憑證驗證（allowInsecure / skip-cert-verify）。",
         "vlessRoute": "嵌入 UUID 的單一 VLESS 路由值（0-65535），例如 443。留空表示無。",
+        "mihomoX25519": "僅 Mihomo：REALITY 握手只使用一般 X25519，不帶 ML-KEM（support-x25519mlkem768: false）。適用於執行 Xray-core 26.9.8 以下、不要求 ML-KEM 的伺服器。",
         "remark": "此 Host 的純文字標籤。僅當入站本身沒有備註時，才作為配置名稱顯示。"
       },
       "remarkVars": {