docs(settings): clarify Sub Port/Sub Domain double as subscription-link fallback (#5721)

* docs(settings): clarify Sub Port/Sub Domain double as subscription-link fallback

subPort/subDomain are documented purely as the subscription service's own
listen address, but when "Reverse Proxy URI" is empty, GetDefaultSettings
silently reuses them (with the admin API request's own Host header as the
domain fallback) to build the subscription link/QR shown in the panel.
Behind a reverse proxy where the sub service listens on an internal port
and is exposed externally on a different port/domain, this produces a
broken link even though "Reverse Proxy URI" already solves it - nothing
in the UI text pointed to it. Clarify all locales.

* docs(settings): fix wording nits from review (punctuation, CJK parens, es-ES field name)

- en-US/id-ID/pt-BR/tr-TR/uk-UA/ar-EG: add terminating punctuation before
  the appended sentence so it doesn't run on directly after the closing
  parenthesis.
- zh-CN/zh-TW/ja-JP: restore full-width CJK parentheses around the
  pre-existing parenthetical, matching the rest of each file.
- es-ES: subURIDesc referenced "Dominio/Puerto de escucha", but the
  actual field labels in this locale are "Dominio de Escucha" and
  "Puerto de Suscripción".

---------

Co-authored-by: Volov <volovdata@google.com>

internal/web/translation/zh-TW.json

@@ -1206,7 +1206,7 @@
       "subListen": "監聽 IP",
       "subListenDesc": "訂閱服務監聽的 IP 地址（留空表示監聽所有 IP）",
       "subPort": "監聽埠",
-      "subPortDesc": "訂閱服務監聽的埠號（必須是未使用的埠）",
+      "subPortDesc": "訂閱服務監聽的埠號（必須是未使用的埠）。當下方「反向代理 URI」為空時，也會用來產生面板中顯示的訂閱連結/QR 碼——如果訂閱是透過反向代理的其他埠存取的，請改為設定「反向代理 URI」。",
       "subCertPath": "公鑰路徑",
       "subCertPathDesc": "訂閱服務使用的公鑰檔案路徑（以 '/' 開頭）",
       "subKeyPath": "私鑰路徑",
@@ -1214,13 +1214,13 @@
       "subPath": "URI 路徑",
       "subPathDesc": "訂閱服務使用的 URI 路徑（以 '/' 開頭，以 '/' 結尾）",
       "subDomain": "監聽域名",
-      "subDomainDesc": "訂閱服務監聽的域名（留空表示監聽所有域名和 IP）",
+      "subDomainDesc": "訂閱服務監聽的域名（留空表示監聽所有域名和 IP）。當「反向代理 URI」為空時，也會作為顯示的訂閱連結的備援域名——如果面板和訂閱透過不同的域名存取(例如位於反向代理之後)，請設定「反向代理 URI」。",
       "subUpdates": "更新間隔",
       "subUpdatesDesc": "客戶端應用中訂閱 URL 的更新間隔（單位：小時）",
       "subEncrypt": "編碼",
       "subEncryptDesc": "訂閱服務返回的內容將採用 Base64 編碼",
       "subURI": "反向代理 URI",
-      "subURIDesc": "用於代理後面的訂閱 URL 的 URI 路徑",
+      "subURIDesc": "用於訂閱連結和 QR 碼的完整基礎 URL(scheme://域名[:埠]/路徑/)，會取代監聽域名/監聽埠使用。當訂閱透過反向代理存取，或使用與上面不同的域名/埠存取時，請設定此項。",
       "externalTrafficInformEnable": "外部交通通知",
       "externalTrafficInformEnableDesc": "每次流量更新時通知外部 API。",
       "externalTrafficInformURI": "外部流量通知 URI",