feat(sub): add per-client subscription HWID limits (#5802)

* feat(sub): add per-client subscription HWID limits

* fix(sub): address HWID review on shared subId and bulk create

* fix(sub): store HWID devices by sub_id and drop anchor client workaround

* fix(sub): restore UA auto-detect and HTML page routing in subs()

The cherry-pick of the HWID gate onto main's refactored SUBController
had dropped main's UA-based format auto-detection and sub-page handling
from subs(). Restore those branches, slotting enforceHwid after the
HTML page and before format detection so the gate only applies to
machine-readable subscription bodies.

Also adapt tests to main's options-struct constructor and to the
ClientService.Update signature extended with limitHwid.

* fix(frontend): drop axios from HttpUtil.delete

The bulk-delete rework's committed version still referenced axios,
which this file no longer imports, breaking typecheck in CI. Use the
httpRequest wrapper like the other verbs.

---------

Co-authored-by: Sanaei <ho3ein.sanaei@gmail.com>

internal/web/translation/en-US.json

@@ -714,6 +714,13 @@
       "addClients": "Add Clients",
       "limitIp": "IP Limit",
       "limitIpDesc": "Maximum simultaneous IPs. 0 = unlimited.",
+      "limitHwid": "HWID Limit",
+      "limitHwidDesc": "Maximum registered devices for subscription requests. 0 = unlimited.",
+      "hwidLog": "HWID Devices",
+      "hwidDevice": "Registered device",
+      "noHwids": "No HWID devices yet",
+      "firstSeen": "First seen",
+      "lastSeen": "Last seen",
       "limitIpFail2banMissing": "Fail2ban is not installed, so the IP limit cannot be enforced. Install Fail2ban from the x-ui bash menu to enable this option.",
       "limitIpFail2banWindows": "Fail2ban is not available on Windows, so the IP limit cannot be enforced.",
       "limitIpDisabled": "The IP limit feature is disabled on this server.",