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/service/client_group_node_sync_test.go

@@ -171,7 +171,7 @@ func TestClientUpdate_ClearsGroup(t *testing.T) {
 	// Edit the client and remove the group.
 	updated := *rec.ToClient()
 	updated.Group = ""
-	if _, err := svc.Update(inboundSvc, rec.Id, updated); err != nil {
+	if _, err := svc.Update(inboundSvc, rec.Id, updated, 0); err != nil {
 		t.Fatalf("Update (clear group): %v", err)
 	}