feat(sub): per-inbound sort order for subscription links

Add a subSortIndex field to inbounds that controls the order of links
in subscription output only: the raw sub body, the HTML sub page, and
the JSON/Clash formats (all served from the same query). Lower values
come first; ties keep id order. The panel inbound list is unaffected.

The value is editable in the inbound form next to the share-address
fields, propagates to nodes via wireInbound, and follows the usual
node-sync rules (copied on import, mirrored while not dirty, never a
structural change).

Rescoped from #5214 by @Ponywka.

internal/web/translation/zh-TW.json

@@ -416,6 +416,7 @@
       },
       "telegramDesc": "請提供Telegram聊天ID。（在機器人中使用'/id'命令）或（{'@'}userinfobot",
       "subscriptionDesc": "要找到你的訂閱 URL，請導航到“詳細資訊”。此外，你可以為多個客戶端使用相同的名稱。",
+      "subSortIndex": "訂閱排序",
       "same": "相同",
       "inboundInfo": "入站資訊",
       "exportInbound": "匯出入站規則",
@@ -595,6 +596,8 @@
         "shareAddrStrategyHelp": "控制匯出分享連結、QR Code 和訂閱輸出時寫入哪個地址。",
         "shareAddr": "自訂分享地址",
         "shareAddrHelp": "僅在分享地址策略為自訂時使用。填寫不帶協定和連接埠的網域或 IP。",
+        "subSortIndex": "訂閱排序",
+        "subSortIndexHelp": "此入站的連結在訂閱輸出（訂閱頁面和客戶端應用）中的位置。數值越小越靠前；數值相同時保持建立順序。不影響面板中的入站清單。",
         "shareAddrStrategyOptions": {
           "node": "節點地址",
           "listen": "入站監聽地址",