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>

frontend/src/generated/examples.ts

@@ -283,6 +283,7 @@ export const EXAMPLES: Record<string, unknown> = {
     "group": "",
     "id": 0,
     "keepAlive": 0,
+    "limitHwid": 0,
     "limitIp": 0,
     "password": "",
     "preSharedKey": "",