feat(nord): support multi-server NordLynx outbounds (#6311)

* feat(nord): support multi-server NordLynx outbounds

* fix(nord): address verified PR review findings

Tighten the NordVPN multi-outbound implementation and its regression
coverage based on the verified review feedback.

- remove the redundant Xray validation test that duplicated the base
  branch and did not exercise multiple outbounds
- make NordModal tests wait for server loading and assert the modal close
  callback, duplicate-server state, and endpoint behavior
- add coverage for resolving the NordLynx public key from technology
  metadata instead of a numeric technology ID
- use a real httptest server for Nord integration tests through an
  injectable API base URL
- represent the All Cities sentinel consistently as null and reset it
  when a country changes

The existing NordVPN API contracts and persisted outbound schema remain
unchanged.

internal/web/translation/id-ID.json

@@ -1852,7 +1852,10 @@
         "noServers": "Tidak ada server ditemukan untuk negara yang dipilih",
         "noPublicKey": "Server yang dipilih tidak mengumumkan kunci publik NordLynx.",
         "outboundAdded": "Outbound NordVPN ditambahkan",
-        "outboundUpdated": "Outbound NordVPN diperbarui"
+        "outboundUpdated": "Outbound NordVPN diperbarui",
+        "serverLoad": "Beban server",
+        "addedServers": "Server yang ditambahkan",
+        "alreadyAdded": "Server ini sudah ada dalam daftar outbound. Gunakan {reset} untuk memperbarui kuncinya."
       },
       "warp": {
         "changeIp": "Ganti IP",